This is libc.info, produced by makeinfo version 4.5 from libc.texinfo.

INFO-DIR-SECTION GNU libraries
START-INFO-DIR-ENTRY
* Libc: (libc).                 C library.
END-INFO-DIR-ENTRY

INFO-DIR-SECTION GNU C library functions and macros
START-INFO-DIR-ENTRY
* ALTWERASE: (libc)Local Modes.
* ARGP_ERR_UNKNOWN: (libc)Argp Parser Functions.
* ARG_MAX: (libc)General Limits.
* BC_BASE_MAX: (libc)Utility Limits.
* BC_DIM_MAX: (libc)Utility Limits.
* BC_SCALE_MAX: (libc)Utility Limits.
* BC_STRING_MAX: (libc)Utility Limits.
* BRKINT: (libc)Input Modes.
* BUFSIZ: (libc)Controlling Buffering.
* CCTS_OFLOW: (libc)Control Modes.
* CHILD_MAX: (libc)General Limits.
* CIGNORE: (libc)Control Modes.
* CLK_TCK: (libc)CPU Time.
* CLOCAL: (libc)Control Modes.
* CLOCKS_PER_SEC: (libc)CPU Time.
* COLL_WEIGHTS_MAX: (libc)Utility Limits.
* CPU_CLR: (libc)CPU Affinity.
* CPU_ISSET: (libc)CPU Affinity.
* CPU_SET: (libc)CPU Affinity.
* CPU_SETSIZE: (libc)CPU Affinity.
* CPU_ZERO: (libc)CPU Affinity.
* CREAD: (libc)Control Modes.
* CRTS_IFLOW: (libc)Control Modes.
* CS5: (libc)Control Modes.
* CS6: (libc)Control Modes.
* CS7: (libc)Control Modes.
* CS8: (libc)Control Modes.
* CSIZE: (libc)Control Modes.
* CSTOPB: (libc)Control Modes.
* DES_FAILED: (libc)DES Encryption.
* DTTOIF: (libc)Directory Entries.
* E2BIG: (libc)Error Codes.
* EACCES: (libc)Error Codes.
* EADDRINUSE: (libc)Error Codes.
* EADDRNOTAVAIL: (libc)Error Codes.
* EADV: (libc)Error Codes.
* EAFNOSUPPORT: (libc)Error Codes.
* EAGAIN: (libc)Error Codes.
* EALREADY: (libc)Error Codes.
* EAUTH: (libc)Error Codes.
* EBACKGROUND: (libc)Error Codes.
* EBADE: (libc)Error Codes.
* EBADF: (libc)Error Codes.
* EBADFD: (libc)Error Codes.
* EBADMSG: (libc)Error Codes.
* EBADR: (libc)Error Codes.
* EBADRPC: (libc)Error Codes.
* EBADRQC: (libc)Error Codes.
* EBADSLT: (libc)Error Codes.
* EBFONT: (libc)Error Codes.
* EBUSY: (libc)Error Codes.
* ECANCELED: (libc)Error Codes.
* ECHILD: (libc)Error Codes.
* ECHO: (libc)Local Modes.
* ECHOCTL: (libc)Local Modes.
* ECHOE: (libc)Local Modes.
* ECHOK: (libc)Local Modes.
* ECHOKE: (libc)Local Modes.
* ECHONL: (libc)Local Modes.
* ECHOPRT: (libc)Local Modes.
* ECHRNG: (libc)Error Codes.
* ECOMM: (libc)Error Codes.
* ECONNABORTED: (libc)Error Codes.
* ECONNREFUSED: (libc)Error Codes.
* ECONNRESET: (libc)Error Codes.
* ED: (libc)Error Codes.
* EDEADLK: (libc)Error Codes.
* EDEADLOCK: (libc)Error Codes.
* EDESTADDRREQ: (libc)Error Codes.
* EDIED: (libc)Error Codes.
* EDOM: (libc)Error Codes.
* EDOTDOT: (libc)Error Codes.
* EDQUOT: (libc)Error Codes.
* EEXIST: (libc)Error Codes.
* EFAULT: (libc)Error Codes.
* EFBIG: (libc)Error Codes.
* EFTYPE: (libc)Error Codes.
* EGRATUITOUS: (libc)Error Codes.
* EGREGIOUS: (libc)Error Codes.
* EHOSTDOWN: (libc)Error Codes.
* EHOSTUNREACH: (libc)Error Codes.
* EIDRM: (libc)Error Codes.
* EIEIO: (libc)Error Codes.
* EILSEQ: (libc)Error Codes.
* EINPROGRESS: (libc)Error Codes.
* EINTR: (libc)Error Codes.
* EINVAL: (libc)Error Codes.
* EIO: (libc)Error Codes.
* EISCONN: (libc)Error Codes.
* EISDIR: (libc)Error Codes.
* EISNAM: (libc)Error Codes.
* EL2HLT: (libc)Error Codes.
* EL2NSYNC: (libc)Error Codes.
* EL3HLT: (libc)Error Codes.
* EL3RST: (libc)Error Codes.
* ELIBACC: (libc)Error Codes.
* ELIBBAD: (libc)Error Codes.
* ELIBEXEC: (libc)Error Codes.
* ELIBMAX: (libc)Error Codes.
* ELIBSCN: (libc)Error Codes.
* ELNRNG: (libc)Error Codes.
* ELOOP: (libc)Error Codes.
* EMEDIUMTYPE: (libc)Error Codes.
* EMFILE: (libc)Error Codes.
* EMLINK: (libc)Error Codes.
* EMSGSIZE: (libc)Error Codes.
* EMULTIHOP: (libc)Error Codes.
* ENAMETOOLONG: (libc)Error Codes.
* ENAVAIL: (libc)Error Codes.
* ENEEDAUTH: (libc)Error Codes.
* ENETDOWN: (libc)Error Codes.
* ENETRESET: (libc)Error Codes.
* ENETUNREACH: (libc)Error Codes.
* ENFILE: (libc)Error Codes.
* ENOANO: (libc)Error Codes.
* ENOBUFS: (libc)Error Codes.
* ENOCSI: (libc)Error Codes.
* ENODATA: (libc)Error Codes.
* ENODEV: (libc)Error Codes.
* ENOENT: (libc)Error Codes.
* ENOEXEC: (libc)Error Codes.
* ENOLCK: (libc)Error Codes.
* ENOLINK: (libc)Error Codes.
* ENOMEDIUM: (libc)Error Codes.
* ENOMEM: (libc)Error Codes.
* ENOMSG: (libc)Error Codes.
* ENONET: (libc)Error Codes.
* ENOPKG: (libc)Error Codes.
* ENOPROTOOPT: (libc)Error Codes.
* ENOSPC: (libc)Error Codes.
* ENOSR: (libc)Error Codes.
* ENOSTR: (libc)Error Codes.
* ENOSYS: (libc)Error Codes.
* ENOTBLK: (libc)Error Codes.
* ENOTCONN: (libc)Error Codes.
* ENOTDIR: (libc)Error Codes.
* ENOTEMPTY: (libc)Error Codes.
* ENOTNAM: (libc)Error Codes.
* ENOTSOCK: (libc)Error Codes.
* ENOTSUP: (libc)Error Codes.
* ENOTTY: (libc)Error Codes.
* ENOTUNIQ: (libc)Error Codes.
* ENXIO: (libc)Error Codes.
* EOF: (libc)EOF and Errors.
* EOPNOTSUPP: (libc)Error Codes.
* EOVERFLOW: (libc)Error Codes.
* EPERM: (libc)Error Codes.
* EPFNOSUPPORT: (libc)Error Codes.
* EPIPE: (libc)Error Codes.
* EPROCLIM: (libc)Error Codes.
* EPROCUNAVAIL: (libc)Error Codes.
* EPROGMISMATCH: (libc)Error Codes.
* EPROGUNAVAIL: (libc)Error Codes.
* EPROTO: (libc)Error Codes.
* EPROTONOSUPPORT: (libc)Error Codes.
* EPROTOTYPE: (libc)Error Codes.
* EQUIV_CLASS_MAX: (libc)Utility Limits.
* ERANGE: (libc)Error Codes.
* EREMCHG: (libc)Error Codes.
* EREMOTE: (libc)Error Codes.
* EREMOTEIO: (libc)Error Codes.
* ERESTART: (libc)Error Codes.
* EROFS: (libc)Error Codes.
* ERPCMISMATCH: (libc)Error Codes.
* ESHUTDOWN: (libc)Error Codes.
* ESOCKTNOSUPPORT: (libc)Error Codes.
* ESPIPE: (libc)Error Codes.
* ESRCH: (libc)Error Codes.
* ESRMNT: (libc)Error Codes.
* ESTALE: (libc)Error Codes.
* ESTRPIPE: (libc)Error Codes.
* ETIME: (libc)Error Codes.
* ETIMEDOUT: (libc)Error Codes.
* ETOOMANYREFS: (libc)Error Codes.
* ETXTBSY: (libc)Error Codes.
* EUCLEAN: (libc)Error Codes.
* EUNATCH: (libc)Error Codes.
* EUSERS: (libc)Error Codes.
* EWOULDBLOCK: (libc)Error Codes.
* EXDEV: (libc)Error Codes.
* EXFULL: (libc)Error Codes.
* EXIT_FAILURE: (libc)Exit Status.
* EXIT_SUCCESS: (libc)Exit Status.
* EXPR_NEST_MAX: (libc)Utility Limits.
* FD_CLOEXEC: (libc)Descriptor Flags.
* FD_CLR: (libc)Waiting for I/O.
* FD_ISSET: (libc)Waiting for I/O.
* FD_SET: (libc)Waiting for I/O.
* FD_SETSIZE: (libc)Waiting for I/O.
* FD_ZERO: (libc)Waiting for I/O.
* FILENAME_MAX: (libc)Limits for Files.
* FLUSHO: (libc)Local Modes.
* FOPEN_MAX: (libc)Opening Streams.
* FP_ILOGB0: (libc)Exponents and Logarithms.
* FP_ILOGBNAN: (libc)Exponents and Logarithms.
* F_DUPFD: (libc)Duplicating Descriptors.
* F_GETFD: (libc)Descriptor Flags.
* F_GETFL: (libc)Getting File Status Flags.
* F_GETLK: (libc)File Locks.
* F_GETOWN: (libc)Interrupt Input.
* F_OK: (libc)Testing File Access.
* F_SETFD: (libc)Descriptor Flags.
* F_SETFL: (libc)Getting File Status Flags.
* F_SETLK: (libc)File Locks.
* F_SETLKW: (libc)File Locks.
* F_SETOWN: (libc)Interrupt Input.
* HUGE_VAL: (libc)Math Error Reporting.
* HUGE_VALF: (libc)Math Error Reporting.
* HUGE_VALL: (libc)Math Error Reporting.
* HUPCL: (libc)Control Modes.
* I: (libc)Complex Numbers.
* ICANON: (libc)Local Modes.
* ICRNL: (libc)Input Modes.
* IEXTEN: (libc)Local Modes.
* IFNAMSIZ: (libc)Interface Naming.
* IFTODT: (libc)Directory Entries.
* IGNBRK: (libc)Input Modes.
* IGNCR: (libc)Input Modes.
* IGNPAR: (libc)Input Modes.
* IMAXBEL: (libc)Input Modes.
* INADDR_ANY: (libc)Host Address Data Type.
* INADDR_BROADCAST: (libc)Host Address Data Type.
* INADDR_LOOPBACK: (libc)Host Address Data Type.
* INADDR_NONE: (libc)Host Address Data Type.
* INFINITY: (libc)Infinity and NaN.
* INLCR: (libc)Input Modes.
* INPCK: (libc)Input Modes.
* IPPORT_RESERVED: (libc)Ports.
* IPPORT_USERRESERVED: (libc)Ports.
* ISIG: (libc)Local Modes.
* ISTRIP: (libc)Input Modes.
* IXANY: (libc)Input Modes.
* IXOFF: (libc)Input Modes.
* IXON: (libc)Input Modes.
* LINE_MAX: (libc)Utility Limits.
* LINK_MAX: (libc)Limits for Files.
* L_ctermid: (libc)Identifying the Terminal.
* L_cuserid: (libc)Who Logged In.
* L_tmpnam: (libc)Temporary Files.
* MAXNAMLEN: (libc)Limits for Files.
* MAXSYMLINKS: (libc)Symbolic Links.
* MAX_CANON: (libc)Limits for Files.
* MAX_INPUT: (libc)Limits for Files.
* MB_CUR_MAX: (libc)Selecting the Conversion.
* MB_LEN_MAX: (libc)Selecting the Conversion.
* MDMBUF: (libc)Control Modes.
* MSG_DONTROUTE: (libc)Socket Data Options.
* MSG_OOB: (libc)Socket Data Options.
* MSG_PEEK: (libc)Socket Data Options.
* NAME_MAX: (libc)Limits for Files.
* NAN: (libc)Infinity and NaN.
* NCCS: (libc)Mode Data Types.
* NGROUPS_MAX: (libc)General Limits.
* NOFLSH: (libc)Local Modes.
* NOKERNINFO: (libc)Local Modes.
* NSIG: (libc)Standard Signals.
* NULL: (libc)Null Pointer Constant.
* ONLCR: (libc)Output Modes.
* ONOEOT: (libc)Output Modes.
* OPEN_MAX: (libc)General Limits.
* OPOST: (libc)Output Modes.
* OXTABS: (libc)Output Modes.
* O_ACCMODE: (libc)Access Modes.
* O_APPEND: (libc)Operating Modes.
* O_ASYNC: (libc)Operating Modes.
* O_CREAT: (libc)Open-time Flags.
* O_EXCL: (libc)Open-time Flags.
* O_EXEC: (libc)Access Modes.
* O_EXLOCK: (libc)Open-time Flags.
* O_FSYNC: (libc)Operating Modes.
* O_IGNORE_CTTY: (libc)Open-time Flags.
* O_NDELAY: (libc)Operating Modes.
* O_NOATIME: (libc)Operating Modes.
* O_NOCTTY: (libc)Open-time Flags.
* O_NOLINK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Operating Modes.
* O_NOTRANS: (libc)Open-time Flags.
* O_RDONLY: (libc)Access Modes.
* O_RDWR: (libc)Access Modes.
* O_READ: (libc)Access Modes.
* O_SHLOCK: (libc)Open-time Flags.
* O_SYNC: (libc)Operating Modes.
* O_TRUNC: (libc)Open-time Flags.
* O_WRITE: (libc)Access Modes.
* O_WRONLY: (libc)Access Modes.
* PARENB: (libc)Control Modes.
* PARMRK: (libc)Input Modes.
* PARODD: (libc)Control Modes.
* PATH_MAX: (libc)Limits for Files.
* PA_FLAG_MASK: (libc)Parsing a Template String.
* PENDIN: (libc)Local Modes.
* PF_FILE: (libc)Local Namespace Details.
* PF_INET6: (libc)Internet Namespace.
* PF_INET: (libc)Internet Namespace.
* PF_LOCAL: (libc)Local Namespace Details.
* PF_UNIX: (libc)Local Namespace Details.
* PIPE_BUF: (libc)Limits for Files.
* P_tmpdir: (libc)Temporary Files.
* RAND_MAX: (libc)ISO Random.
* RE_DUP_MAX: (libc)General Limits.
* RLIM_INFINITY: (libc)Limits on Resources.
* R_OK: (libc)Testing File Access.
* SA_NOCLDSTOP: (libc)Flags for Sigaction.
* SA_ONSTACK: (libc)Flags for Sigaction.
* SA_RESTART: (libc)Flags for Sigaction.
* SEEK_CUR: (libc)File Positioning.
* SEEK_END: (libc)File Positioning.
* SEEK_SET: (libc)File Positioning.
* SIGABRT: (libc)Program Error Signals.
* SIGALRM: (libc)Alarm Signals.
* SIGBUS: (libc)Program Error Signals.
* SIGCHLD: (libc)Job Control Signals.
* SIGCLD: (libc)Job Control Signals.
* SIGCONT: (libc)Job Control Signals.
* SIGEMT: (libc)Program Error Signals.
* SIGFPE: (libc)Program Error Signals.
* SIGHUP: (libc)Termination Signals.
* SIGILL: (libc)Program Error Signals.
* SIGINFO: (libc)Miscellaneous Signals.
* SIGINT: (libc)Termination Signals.
* SIGIO: (libc)Asynchronous I/O Signals.
* SIGIOT: (libc)Program Error Signals.
* SIGKILL: (libc)Termination Signals.
* SIGLOST: (libc)Operation Error Signals.
* SIGPIPE: (libc)Operation Error Signals.
* SIGPOLL: (libc)Asynchronous I/O Signals.
* SIGPROF: (libc)Alarm Signals.
* SIGQUIT: (libc)Termination Signals.
* SIGSEGV: (libc)Program Error Signals.
* SIGSTOP: (libc)Job Control Signals.
* SIGSYS: (libc)Program Error Signals.
* SIGTERM: (libc)Termination Signals.
* SIGTRAP: (libc)Program Error Signals.
* SIGTSTP: (libc)Job Control Signals.
* SIGTTIN: (libc)Job Control Signals.
* SIGTTOU: (libc)Job Control Signals.
* SIGURG: (libc)Asynchronous I/O Signals.
* SIGUSR1: (libc)Miscellaneous Signals.
* SIGUSR2: (libc)Miscellaneous Signals.
* SIGVTALRM: (libc)Alarm Signals.
* SIGWINCH: (libc)Miscellaneous Signals.
* SIGXCPU: (libc)Operation Error Signals.
* SIGXFSZ: (libc)Operation Error Signals.
* SIG_ERR: (libc)Basic Signal Handling.
* SOCK_DGRAM: (libc)Communication Styles.
* SOCK_RAW: (libc)Communication Styles.
* SOCK_RDM: (libc)Communication Styles.
* SOCK_SEQPACKET: (libc)Communication Styles.
* SOCK_STREAM: (libc)Communication Styles.
* SOL_SOCKET: (libc)Socket-Level Options.
* SSIZE_MAX: (libc)General Limits.
* STREAM_MAX: (libc)General Limits.
* SUN_LEN: (libc)Local Namespace Details.
* SV_INTERRUPT: (libc)BSD Handler.
* SV_ONSTACK: (libc)BSD Handler.
* SV_RESETHAND: (libc)BSD Handler.
* S_IFMT: (libc)Testing File Type.
* S_ISBLK: (libc)Testing File Type.
* S_ISCHR: (libc)Testing File Type.
* S_ISDIR: (libc)Testing File Type.
* S_ISFIFO: (libc)Testing File Type.
* S_ISLNK: (libc)Testing File Type.
* S_ISREG: (libc)Testing File Type.
* S_ISSOCK: (libc)Testing File Type.
* S_TYPEISMQ: (libc)Testing File Type.
* S_TYPEISSEM: (libc)Testing File Type.
* S_TYPEISSHM: (libc)Testing File Type.
* TMP_MAX: (libc)Temporary Files.
* TOSTOP: (libc)Local Modes.
* TZNAME_MAX: (libc)General Limits.
* VDISCARD: (libc)Other Special.
* VDSUSP: (libc)Signal Characters.
* VEOF: (libc)Editing Characters.
* VEOL2: (libc)Editing Characters.
* VEOL: (libc)Editing Characters.
* VERASE: (libc)Editing Characters.
* VINTR: (libc)Signal Characters.
* VKILL: (libc)Editing Characters.
* VLNEXT: (libc)Other Special.
* VMIN: (libc)Noncanonical Input.
* VQUIT: (libc)Signal Characters.
* VREPRINT: (libc)Editing Characters.
* VSTART: (libc)Start/Stop Characters.
* VSTATUS: (libc)Other Special.
* VSTOP: (libc)Start/Stop Characters.
* VSUSP: (libc)Signal Characters.
* VTIME: (libc)Noncanonical Input.
* VWERASE: (libc)Editing Characters.
* WCHAR_MAX: (libc)Extended Char Intro.
* WCHAR_MIN: (libc)Extended Char Intro.
* WCOREDUMP: (libc)Process Completion Status.
* WEOF: (libc)EOF and Errors.
* WEOF: (libc)Extended Char Intro.
* WEXITSTATUS: (libc)Process Completion Status.
* WIFEXITED: (libc)Process Completion Status.
* WIFSIGNALED: (libc)Process Completion Status.
* WIFSTOPPED: (libc)Process Completion Status.
* WSTOPSIG: (libc)Process Completion Status.
* WTERMSIG: (libc)Process Completion Status.
* W_OK: (libc)Testing File Access.
* X_OK: (libc)Testing File Access.
* _Complex_I: (libc)Complex Numbers.
* _Exit: (libc)Termination Internals.
* _IOFBF: (libc)Controlling Buffering.
* _IOLBF: (libc)Controlling Buffering.
* _IONBF: (libc)Controlling Buffering.
* _Imaginary_I: (libc)Complex Numbers.
* _PATH_UTMP: (libc)Manipulating the Database.
* _PATH_WTMP: (libc)Manipulating the Database.
* _POSIX2_C_DEV: (libc)System Options.
* _POSIX2_C_VERSION: (libc)Version Supported.
* _POSIX2_FORT_DEV: (libc)System Options.
* _POSIX2_FORT_RUN: (libc)System Options.
* _POSIX2_LOCALEDEF: (libc)System Options.
* _POSIX2_SW_DEV: (libc)System Options.
* _POSIX_CHOWN_RESTRICTED: (libc)Options for Files.
* _POSIX_JOB_CONTROL: (libc)System Options.
* _POSIX_NO_TRUNC: (libc)Options for Files.
* _POSIX_SAVED_IDS: (libc)System Options.
* _POSIX_VDISABLE: (libc)Options for Files.
* _POSIX_VERSION: (libc)Version Supported.
* __fbufsize: (libc)Controlling Buffering.
* __flbf: (libc)Controlling Buffering.
* __fpending: (libc)Controlling Buffering.
* __fpurge: (libc)Flushing Buffers.
* __freadable: (libc)Opening Streams.
* __freading: (libc)Opening Streams.
* __fsetlocking: (libc)Streams and Threads.
* __fwritable: (libc)Opening Streams.
* __fwriting: (libc)Opening Streams.
* __gconv_end_fct: (libc)glibc iconv Implementation.
* __gconv_fct: (libc)glibc iconv Implementation.
* __gconv_init_fct: (libc)glibc iconv Implementation.
* __va_copy: (libc)Argument Macros.
* _exit: (libc)Termination Internals.
* _flushlbf: (libc)Flushing Buffers.
* _tolower: (libc)Case Conversion.
* _toupper: (libc)Case Conversion.
* a64l: (libc)Encode Binary Data.
* abort: (libc)Aborting a Program.
* abs: (libc)Absolute Value.
* accept: (libc)Accepting Connections.
* access: (libc)Testing File Access.
* acos: (libc)Inverse Trig Functions.
* acosf: (libc)Inverse Trig Functions.
* acosh: (libc)Hyperbolic Functions.
* acoshf: (libc)Hyperbolic Functions.
* acoshl: (libc)Hyperbolic Functions.
* acosl: (libc)Inverse Trig Functions.
* addmntent: (libc)mtab.
* addseverity: (libc)Adding Severity Classes.
* adjtime: (libc)High-Resolution Calendar.
* adjtimex: (libc)High-Resolution Calendar.
* aio_cancel64: (libc)Cancel AIO Operations.
* aio_cancel: (libc)Cancel AIO Operations.
* aio_error64: (libc)Status of AIO Operations.
* aio_error: (libc)Status of AIO Operations.
* aio_fsync64: (libc)Synchronizing AIO Operations.
* aio_fsync: (libc)Synchronizing AIO Operations.
* aio_init: (libc)Configuration of AIO.
* aio_read64: (libc)Asynchronous Reads/Writes.
* aio_read: (libc)Asynchronous Reads/Writes.
* aio_return64: (libc)Status of AIO Operations.
* aio_return: (libc)Status of AIO Operations.
* aio_suspend64: (libc)Synchronizing AIO Operations.
* aio_suspend: (libc)Synchronizing AIO Operations.
* aio_write64: (libc)Asynchronous Reads/Writes.
* aio_write: (libc)Asynchronous Reads/Writes.
* alarm: (libc)Setting an Alarm.
* alloca: (libc)Variable Size Automatic.
* alphasort64: (libc)Scanning Directory Content.
* alphasort: (libc)Scanning Directory Content.
* argp_error: (libc)Argp Helper Functions.
* argp_failure: (libc)Argp Helper Functions.
* argp_help: (libc)Argp Help.
* argp_parse: (libc)Argp.
* argp_state_help: (libc)Argp Helper Functions.
* argp_usage: (libc)Argp Helper Functions.
* argz_add: (libc)Argz Functions.
* argz_add_sep: (libc)Argz Functions.
* argz_append: (libc)Argz Functions.
* argz_count: (libc)Argz Functions.
* argz_create: (libc)Argz Functions.
* argz_create_sep: (libc)Argz Functions.
* argz_delete: (libc)Argz Functions.
* argz_extract: (libc)Argz Functions.
* argz_insert: (libc)Argz Functions.
* argz_next: (libc)Argz Functions.
* argz_replace: (libc)Argz Functions.
* argz_stringify: (libc)Argz Functions.
* asctime: (libc)Formatting Calendar Time.
* asctime_r: (libc)Formatting Calendar Time.
* asin: (libc)Inverse Trig Functions.
* asinf: (libc)Inverse Trig Functions.
* asinh: (libc)Hyperbolic Functions.
* asinhf: (libc)Hyperbolic Functions.
* asinhl: (libc)Hyperbolic Functions.
* asinl: (libc)Inverse Trig Functions.
* asprintf: (libc)Dynamic Output.
* assert: (libc)Consistency Checking.
* assert_perror: (libc)Consistency Checking.
* atan2: (libc)Inverse Trig Functions.
* atan2f: (libc)Inverse Trig Functions.
* atan2l: (libc)Inverse Trig Functions.
* atan: (libc)Inverse Trig Functions.
* atanf: (libc)Inverse Trig Functions.
* atanh: (libc)Hyperbolic Functions.
* atanhf: (libc)Hyperbolic Functions.
* atanhl: (libc)Hyperbolic Functions.
* atanl: (libc)Inverse Trig Functions.
* atexit: (libc)Cleanups on Exit.
* atof: (libc)Parsing of Floats.
* atoi: (libc)Parsing of Integers.
* atol: (libc)Parsing of Integers.
* atoll: (libc)Parsing of Integers.
* backtrace: (libc)Backtraces.
* backtrace_symbols: (libc)Backtraces.
* backtrace_symbols_fd: (libc)Backtraces.
* basename: (libc)Finding Tokens in a String.
* basename: (libc)Finding Tokens in a String.
* bcmp: (libc)String/Array Comparison.
* bcopy: (libc)Copying and Concatenation.
* bind: (libc)Setting Address.
* bind_textdomain_codeset: (libc)Charset conversion in gettext.
* bindtextdomain: (libc)Locating gettext catalog.
* brk: (libc)Resizing the Data Segment.
* bsearch: (libc)Array Search Function.
* btowc: (libc)Converting a Character.
* bzero: (libc)Copying and Concatenation.
* cabs: (libc)Absolute Value.
* cabsf: (libc)Absolute Value.
* cabsl: (libc)Absolute Value.
* cacos: (libc)Inverse Trig Functions.
* cacosf: (libc)Inverse Trig Functions.
* cacosh: (libc)Hyperbolic Functions.
* cacoshf: (libc)Hyperbolic Functions.
* cacoshl: (libc)Hyperbolic Functions.
* cacosl: (libc)Inverse Trig Functions.
* calloc: (libc)Allocating Cleared Space.
* canonicalize_file_name: (libc)Symbolic Links.
* carg: (libc)Operations on Complex.
* cargf: (libc)Operations on Complex.
* cargl: (libc)Operations on Complex.
* casin: (libc)Inverse Trig Functions.
* casinf: (libc)Inverse Trig Functions.
* casinh: (libc)Hyperbolic Functions.
* casinhf: (libc)Hyperbolic Functions.
* casinhl: (libc)Hyperbolic Functions.
* casinl: (libc)Inverse Trig Functions.
* catan: (libc)Inverse Trig Functions.
* catanf: (libc)Inverse Trig Functions.
* catanh: (libc)Hyperbolic Functions.
* catanhf: (libc)Hyperbolic Functions.
* catanhl: (libc)Hyperbolic Functions.
* catanl: (libc)Inverse Trig Functions.
* catclose: (libc)The catgets Functions.
* catgets: (libc)The catgets Functions.
* catopen: (libc)The catgets Functions.
* cbc_crypt: (libc)DES Encryption.
* cbrt: (libc)Exponents and Logarithms.
* cbrtf: (libc)Exponents and Logarithms.
* cbrtl: (libc)Exponents and Logarithms.
* ccos: (libc)Trig Functions.
* ccosf: (libc)Trig Functions.
* ccosh: (libc)Hyperbolic Functions.
* ccoshf: (libc)Hyperbolic Functions.
* ccoshl: (libc)Hyperbolic Functions.
* ccosl: (libc)Trig Functions.
* ceil: (libc)Rounding Functions.
* ceilf: (libc)Rounding Functions.
* ceill: (libc)Rounding Functions.
* cexp: (libc)Exponents and Logarithms.
* cexpf: (libc)Exponents and Logarithms.
* cexpl: (libc)Exponents and Logarithms.
* cfgetispeed: (libc)Line Speed.
* cfgetospeed: (libc)Line Speed.
* cfmakeraw: (libc)Noncanonical Input.
* cfree: (libc)Freeing after Malloc.
* cfsetispeed: (libc)Line Speed.
* cfsetospeed: (libc)Line Speed.
* cfsetspeed: (libc)Line Speed.
* chdir: (libc)Working Directory.
* chmod: (libc)Setting Permissions.
* chown: (libc)File Owner.
* cimag: (libc)Operations on Complex.
* cimagf: (libc)Operations on Complex.
* cimagl: (libc)Operations on Complex.
* clearenv: (libc)Environment Access.
* clearerr: (libc)Error Recovery.
* clearerr_unlocked: (libc)Error Recovery.
* clock: (libc)CPU Time.
* clog10: (libc)Exponents and Logarithms.
* clog10f: (libc)Exponents and Logarithms.
* clog10l: (libc)Exponents and Logarithms.
* clog: (libc)Exponents and Logarithms.
* clogf: (libc)Exponents and Logarithms.
* clogl: (libc)Exponents and Logarithms.
* close: (libc)Opening and Closing Files.
* closedir: (libc)Reading/Closing Directory.
* closelog: (libc)closelog.
* confstr: (libc)String Parameters.
* conj: (libc)Operations on Complex.
* conjf: (libc)Operations on Complex.
* conjl: (libc)Operations on Complex.
* connect: (libc)Connecting.
* copysign: (libc)FP Bit Twiddling.
* copysignf: (libc)FP Bit Twiddling.
* copysignl: (libc)FP Bit Twiddling.
* cos: (libc)Trig Functions.
* cosf: (libc)Trig Functions.
* cosh: (libc)Hyperbolic Functions.
* coshf: (libc)Hyperbolic Functions.
* coshl: (libc)Hyperbolic Functions.
* cosl: (libc)Trig Functions.
* cpow: (libc)Exponents and Logarithms.
* cpowf: (libc)Exponents and Logarithms.
* cpowl: (libc)Exponents and Logarithms.
* cproj: (libc)Operations on Complex.
* cprojf: (libc)Operations on Complex.
* cprojl: (libc)Operations on Complex.
* creal: (libc)Operations on Complex.
* crealf: (libc)Operations on Complex.
* creall: (libc)Operations on Complex.
* creat64: (libc)Opening and Closing Files.
* creat: (libc)Opening and Closing Files.
* crypt: (libc)crypt.
* crypt_r: (libc)crypt.
* csin: (libc)Trig Functions.
* csinf: (libc)Trig Functions.
* csinh: (libc)Hyperbolic Functions.
* csinhf: (libc)Hyperbolic Functions.
* csinhl: (libc)Hyperbolic Functions.
* csinl: (libc)Trig Functions.
* csqrt: (libc)Exponents and Logarithms.
* csqrtf: (libc)Exponents and Logarithms.
* csqrtl: (libc)Exponents and Logarithms.
* ctan: (libc)Trig Functions.
* ctanf: (libc)Trig Functions.
* ctanh: (libc)Hyperbolic Functions.
* ctanhf: (libc)Hyperbolic Functions.
* ctanhl: (libc)Hyperbolic Functions.
* ctanl: (libc)Trig Functions.
* ctermid: (libc)Identifying the Terminal.
* ctime: (libc)Formatting Calendar Time.
* ctime_r: (libc)Formatting Calendar Time.
* cuserid: (libc)Who Logged In.
* dcgettext: (libc)Translation with gettext.
* dcngettext: (libc)Advanced gettext functions.
* des_setparity: (libc)DES Encryption.
* dgettext: (libc)Translation with gettext.
* difftime: (libc)Elapsed Time.
* dirfd: (libc)Opening a Directory.
* dirname: (libc)Finding Tokens in a String.
* div: (libc)Integer Division.
* dngettext: (libc)Advanced gettext functions.
* drand48: (libc)SVID Random.
* drand48_r: (libc)SVID Random.
* drem: (libc)Remainder Functions.
* dremf: (libc)Remainder Functions.
* dreml: (libc)Remainder Functions.
* dup2: (libc)Duplicating Descriptors.
* dup: (libc)Duplicating Descriptors.
* ecb_crypt: (libc)DES Encryption.
* ecvt: (libc)System V Number Conversion.
* ecvt_r: (libc)System V Number Conversion.
* encrypt: (libc)DES Encryption.
* encrypt_r: (libc)DES Encryption.
* endfsent: (libc)fstab.
* endgrent: (libc)Scanning All Groups.
* endhostent: (libc)Host Names.
* endmntent: (libc)mtab.
* endnetent: (libc)Networks Database.
* endnetgrent: (libc)Lookup Netgroup.
* endprotoent: (libc)Protocols Database.
* endpwent: (libc)Scanning All Users.
* endservent: (libc)Services Database.
* endutent: (libc)Manipulating the Database.
* endutxent: (libc)XPG Functions.
* envz_add: (libc)Envz Functions.
* envz_entry: (libc)Envz Functions.
* envz_get: (libc)Envz Functions.
* envz_merge: (libc)Envz Functions.
* envz_strip: (libc)Envz Functions.
* erand48: (libc)SVID Random.
* erand48_r: (libc)SVID Random.
* erf: (libc)Special Functions.
* erfc: (libc)Special Functions.
* erfcf: (libc)Special Functions.
* erfcl: (libc)Special Functions.
* erff: (libc)Special Functions.
* erfl: (libc)Special Functions.
* err: (libc)Error Messages.
* errno: (libc)Checking for Errors.
* error: (libc)Error Messages.
* error_at_line: (libc)Error Messages.
* errx: (libc)Error Messages.
* execl: (libc)Executing a File.
* execle: (libc)Executing a File.
* execlp: (libc)Executing a File.
* execv: (libc)Executing a File.
* execve: (libc)Executing a File.
* execvp: (libc)Executing a File.
* exit: (libc)Normal Termination.
* exp10: (libc)Exponents and Logarithms.
* exp10f: (libc)Exponents and Logarithms.
* exp10l: (libc)Exponents and Logarithms.
* exp2: (libc)Exponents and Logarithms.
* exp2f: (libc)Exponents and Logarithms.
* exp2l: (libc)Exponents and Logarithms.
* exp: (libc)Exponents and Logarithms.
* expf: (libc)Exponents and Logarithms.
* expl: (libc)Exponents and Logarithms.
* expm1: (libc)Exponents and Logarithms.
* expm1f: (libc)Exponents and Logarithms.
* expm1l: (libc)Exponents and Logarithms.
* fabs: (libc)Absolute Value.
* fabsf: (libc)Absolute Value.
* fabsl: (libc)Absolute Value.
* fchdir: (libc)Working Directory.
* fchmod: (libc)Setting Permissions.
* fchown: (libc)File Owner.
* fclean: (libc)Cleaning Streams.
* fclose: (libc)Closing Streams.
* fcloseall: (libc)Closing Streams.
* fcntl: (libc)Control Operations.
* fcvt: (libc)System V Number Conversion.
* fcvt_r: (libc)System V Number Conversion.
* fdatasync: (libc)Synchronizing I/O.
* fdim: (libc)Misc FP Arithmetic.
* fdimf: (libc)Misc FP Arithmetic.
* fdiml: (libc)Misc FP Arithmetic.
* fdopen: (libc)Descriptors and Streams.
* feclearexcept: (libc)Status bit operations.
* fedisableexcept: (libc)Control Functions.
* feenableexcept: (libc)Control Functions.
* fegetenv: (libc)Control Functions.
* fegetexcept: (libc)Control Functions.
* fegetexceptflag: (libc)Status bit operations.
* fegetround: (libc)Rounding.
* feholdexcept: (libc)Control Functions.
* feof: (libc)EOF and Errors.
* feof_unlocked: (libc)EOF and Errors.
* feraiseexcept: (libc)Status bit operations.
* ferror: (libc)EOF and Errors.
* ferror_unlocked: (libc)EOF and Errors.
* fesetenv: (libc)Control Functions.
* fesetexceptflag: (libc)Status bit operations.
* fesetround: (libc)Rounding.
* fetestexcept: (libc)Status bit operations.
* feupdateenv: (libc)Control Functions.
* fflush: (libc)Flushing Buffers.
* fflush_unlocked: (libc)Flushing Buffers.
* fgetc: (libc)Character Input.
* fgetc_unlocked: (libc)Character Input.
* fgetgrent: (libc)Scanning All Groups.
* fgetgrent_r: (libc)Scanning All Groups.
* fgetpos64: (libc)Portable Positioning.
* fgetpos: (libc)Portable Positioning.
* fgetpwent: (libc)Scanning All Users.
* fgetpwent_r: (libc)Scanning All Users.
* fgets: (libc)Line Input.
* fgets_unlocked: (libc)Line Input.
* fgetwc: (libc)Character Input.
* fgetwc_unlocked: (libc)Character Input.
* fgetws: (libc)Line Input.
* fgetws_unlocked: (libc)Line Input.
* fileno: (libc)Descriptors and Streams.
* fileno_unlocked: (libc)Descriptors and Streams.
* finite: (libc)Floating Point Classes.
* finitef: (libc)Floating Point Classes.
* finitel: (libc)Floating Point Classes.
* flockfile: (libc)Streams and Threads.
* floor: (libc)Rounding Functions.
* floorf: (libc)Rounding Functions.
* floorl: (libc)Rounding Functions.
* fma: (libc)Misc FP Arithmetic.
* fmaf: (libc)Misc FP Arithmetic.
* fmal: (libc)Misc FP Arithmetic.
* fmax: (libc)Misc FP Arithmetic.
* fmaxf: (libc)Misc FP Arithmetic.
* fmaxl: (libc)Misc FP Arithmetic.
* fmemopen: (libc)String Streams.
* fmin: (libc)Misc FP Arithmetic.
* fminf: (libc)Misc FP Arithmetic.
* fminl: (libc)Misc FP Arithmetic.
* fmod: (libc)Remainder Functions.
* fmodf: (libc)Remainder Functions.
* fmodl: (libc)Remainder Functions.
* fmtmsg: (libc)Printing Formatted Messages.
* fnmatch: (libc)Wildcard Matching.
* fopen64: (libc)Opening Streams.
* fopen: (libc)Opening Streams.
* fopencookie: (libc)Streams and Cookies.
* fork: (libc)Creating a Process.
* forkpty: (libc)Pseudo-Terminal Pairs.
* fpathconf: (libc)Pathconf.
* fpclassify: (libc)Floating Point Classes.
* fprintf: (libc)Formatted Output Functions.
* fputc: (libc)Simple Output.
* fputc_unlocked: (libc)Simple Output.
* fputs: (libc)Simple Output.
* fputs_unlocked: (libc)Simple Output.
* fputwc: (libc)Simple Output.
* fputwc_unlocked: (libc)Simple Output.
* fputws: (libc)Simple Output.
* fputws_unlocked: (libc)Simple Output.
* fread: (libc)Block Input/Output.
* fread_unlocked: (libc)Block Input/Output.
* free: (libc)Freeing after Malloc.
* freopen64: (libc)Opening Streams.
* freopen: (libc)Opening Streams.
* frexp: (libc)Normalization Functions.
* frexpf: (libc)Normalization Functions.
* frexpl: (libc)Normalization Functions.
* fscanf: (libc)Formatted Input Functions.
* fseek: (libc)File Positioning.
* fseeko64: (libc)File Positioning.
* fseeko: (libc)File Positioning.
* fsetpos64: (libc)Portable Positioning.
* fsetpos: (libc)Portable Positioning.
* fstat64: (libc)Reading Attributes.
* fstat: (libc)Reading Attributes.
* fsync: (libc)Synchronizing I/O.
* ftell: (libc)File Positioning.
* ftello64: (libc)File Positioning.
* ftello: (libc)File Positioning.
* ftruncate64: (libc)File Size.
* ftruncate: (libc)File Size.
* ftrylockfile: (libc)Streams and Threads.
* ftw64: (libc)Working with Directory Trees.
* ftw: (libc)Working with Directory Trees.
* funlockfile: (libc)Streams and Threads.
* futimes: (libc)File Times.
* fwide: (libc)Streams and I18N.
* fwprintf: (libc)Formatted Output Functions.
* fwrite: (libc)Block Input/Output.
* fwrite_unlocked: (libc)Block Input/Output.
* fwscanf: (libc)Formatted Input Functions.
* gamma: (libc)Special Functions.
* gammaf: (libc)Special Functions.
* gammal: (libc)Special Functions.
* gcvt: (libc)System V Number Conversion.
* get_avphys_pages: (libc)Query Memory Parameters.
* get_current_dir_name: (libc)Working Directory.
* get_nprocs: (libc)Processor Resources.
* get_nprocs_conf: (libc)Processor Resources.
* get_phys_pages: (libc)Query Memory Parameters.
* getc: (libc)Character Input.
* getc_unlocked: (libc)Character Input.
* getchar: (libc)Character Input.
* getchar_unlocked: (libc)Character Input.
* getcontext: (libc)System V contexts.
* getcwd: (libc)Working Directory.
* getdate: (libc)General Time String Parsing.
* getdate_r: (libc)General Time String Parsing.
* getdelim: (libc)Line Input.
* getdomainnname: (libc)Host Identification.
* getegid: (libc)Reading Persona.
* getenv: (libc)Environment Access.
* geteuid: (libc)Reading Persona.
* getfsent: (libc)fstab.
* getfsfile: (libc)fstab.
* getfsspec: (libc)fstab.
* getgid: (libc)Reading Persona.
* getgrent: (libc)Scanning All Groups.
* getgrent_r: (libc)Scanning All Groups.
* getgrgid: (libc)Lookup Group.
* getgrgid_r: (libc)Lookup Group.
* getgrnam: (libc)Lookup Group.
* getgrnam_r: (libc)Lookup Group.
* getgrouplist: (libc)Setting Groups.
* getgroups: (libc)Reading Persona.
* gethostbyaddr: (libc)Host Names.
* gethostbyaddr_r: (libc)Host Names.
* gethostbyname2: (libc)Host Names.
* gethostbyname2_r: (libc)Host Names.
* gethostbyname: (libc)Host Names.
* gethostbyname_r: (libc)Host Names.
* gethostent: (libc)Host Names.
* gethostid: (libc)Host Identification.
* gethostname: (libc)Host Identification.
* getitimer: (libc)Setting an Alarm.
* getline: (libc)Line Input.
* getloadavg: (libc)Processor Resources.
* getlogin: (libc)Who Logged In.
* getmntent: (libc)mtab.
* getmntent_r: (libc)mtab.
* getnetbyaddr: (libc)Networks Database.
* getnetbyname: (libc)Networks Database.
* getnetent: (libc)Networks Database.
* getnetgrent: (libc)Lookup Netgroup.
* getnetgrent_r: (libc)Lookup Netgroup.
* getopt: (libc)Using Getopt.
* getopt_long: (libc)Getopt Long Options.
* getopt_long_only: (libc)Getopt Long Options.
* getpagesize: (libc)Query Memory Parameters.
* getpass: (libc)getpass.
* getpeername: (libc)Who is Connected.
* getpgid: (libc)Process Group Functions.
* getpgrp: (libc)Process Group Functions.
* getpgrp: (libc)Process Group Functions.
* getpid: (libc)Process Identification.
* getppid: (libc)Process Identification.
* getpriority: (libc)Traditional Scheduling Functions.
* getprotobyname: (libc)Protocols Database.
* getprotobynumber: (libc)Protocols Database.
* getprotoent: (libc)Protocols Database.
* getpt: (libc)Allocation.
* getpwent: (libc)Scanning All Users.
* getpwent_r: (libc)Scanning All Users.
* getpwnam: (libc)Lookup User.
* getpwnam_r: (libc)Lookup User.
* getpwuid: (libc)Lookup User.
* getpwuid_r: (libc)Lookup User.
* getrlimit64: (libc)Limits on Resources.
* getrlimit: (libc)Limits on Resources.
* getrusage: (libc)Resource Usage.
* gets: (libc)Line Input.
* getservbyname: (libc)Services Database.
* getservbyport: (libc)Services Database.
* getservent: (libc)Services Database.
* getsid: (libc)Process Group Functions.
* getsockname: (libc)Reading Address.
* getsockopt: (libc)Socket Option Functions.
* getsubopt: (libc)Suboptions.
* gettext: (libc)Translation with gettext.
* gettimeofday: (libc)High-Resolution Calendar.
* getuid: (libc)Reading Persona.
* getumask: (libc)Setting Permissions.
* getutent: (libc)Manipulating the Database.
* getutent_r: (libc)Manipulating the Database.
* getutid: (libc)Manipulating the Database.
* getutid_r: (libc)Manipulating the Database.
* getutline: (libc)Manipulating the Database.
* getutline_r: (libc)Manipulating the Database.
* getutmp: (libc)XPG Functions.
* getutmpx: (libc)XPG Functions.
* getutxent: (libc)XPG Functions.
* getutxid: (libc)XPG Functions.
* getutxline: (libc)XPG Functions.
* getw: (libc)Character Input.
* getwc: (libc)Character Input.
* getwc_unlocked: (libc)Character Input.
* getwchar: (libc)Character Input.
* getwchar_unlocked: (libc)Character Input.
* getwd: (libc)Working Directory.
* glob64: (libc)Calling Glob.
* glob: (libc)Calling Glob.
* globfree64: (libc)More Flags for Globbing.
* globfree: (libc)More Flags for Globbing.
* gmtime: (libc)Broken-down Time.
* gmtime_r: (libc)Broken-down Time.
* grantpt: (libc)Allocation.
* gsignal: (libc)Signaling Yourself.
* gtty: (libc)BSD Terminal Modes.
* hasmntopt: (libc)mtab.
* hcreate: (libc)Hash Search Function.
* hcreate_r: (libc)Hash Search Function.
* hdestroy: (libc)Hash Search Function.
* hdestroy_r: (libc)Hash Search Function.
* hsearch: (libc)Hash Search Function.
* hsearch_r: (libc)Hash Search Function.
* htonl: (libc)Byte Order.
* htons: (libc)Byte Order.
* hypot: (libc)Exponents and Logarithms.
* hypotf: (libc)Exponents and Logarithms.
* hypotl: (libc)Exponents and Logarithms.
* iconv: (libc)Generic Conversion Interface.
* iconv_close: (libc)Generic Conversion Interface.
* iconv_open: (libc)Generic Conversion Interface.
* if_freenameindex: (libc)Interface Naming.
* if_indextoname: (libc)Interface Naming.
* if_nameindex: (libc)Interface Naming.
* if_nametoindex: (libc)Interface Naming.
* ilogb: (libc)Exponents and Logarithms.
* ilogbf: (libc)Exponents and Logarithms.
* ilogbl: (libc)Exponents and Logarithms.
* imaxabs: (libc)Absolute Value.
* imaxdiv: (libc)Integer Division.
* in6addr_any: (libc)Host Address Data Type.
* in6addr_loopback: (libc)Host Address Data Type.
* index: (libc)Search Functions.
* inet_addr: (libc)Host Address Functions.
* inet_aton: (libc)Host Address Functions.
* inet_lnaof: (libc)Host Address Functions.
* inet_makeaddr: (libc)Host Address Functions.
* inet_netof: (libc)Host Address Functions.
* inet_network: (libc)Host Address Functions.
* inet_ntoa: (libc)Host Address Functions.
* inet_ntop: (libc)Host Address Functions.
* inet_pton: (libc)Host Address Functions.
* initgroups: (libc)Setting Groups.
* initstate: (libc)BSD Random.
* initstate_r: (libc)BSD Random.
* innetgr: (libc)Netgroup Membership.
* ioctl: (libc)IOCTLs.
* isalnum: (libc)Classification of Characters.
* isalpha: (libc)Classification of Characters.
* isascii: (libc)Classification of Characters.
* isatty: (libc)Is It a Terminal.
* isblank: (libc)Classification of Characters.
* iscntrl: (libc)Classification of Characters.
* isdigit: (libc)Classification of Characters.
* isfinite: (libc)Floating Point Classes.
* isgraph: (libc)Classification of Characters.
* isgreater: (libc)FP Comparison Functions.
* isgreaterequal: (libc)FP Comparison Functions.
* isinf: (libc)Floating Point Classes.
* isinff: (libc)Floating Point Classes.
* isinfl: (libc)Floating Point Classes.
* isless: (libc)FP Comparison Functions.
* islessequal: (libc)FP Comparison Functions.
* islessgreater: (libc)FP Comparison Functions.
* islower: (libc)Classification of Characters.
* isnan: (libc)Floating Point Classes.
* isnan: (libc)Floating Point Classes.
* isnanf: (libc)Floating Point Classes.
* isnanl: (libc)Floating Point Classes.
* isnormal: (libc)Floating Point Classes.
* isprint: (libc)Classification of Characters.
* ispunct: (libc)Classification of Characters.
* isspace: (libc)Classification of Characters.
* isunordered: (libc)FP Comparison Functions.
* isupper: (libc)Classification of Characters.
* iswalnum: (libc)Classification of Wide Characters.
* iswalpha: (libc)Classification of Wide Characters.
* iswblank: (libc)Classification of Wide Characters.
* iswcntrl: (libc)Classification of Wide Characters.
* iswctype: (libc)Classification of Wide Characters.
* iswdigit: (libc)Classification of Wide Characters.
* iswgraph: (libc)Classification of Wide Characters.
* iswlower: (libc)Classification of Wide Characters.
* iswprint: (libc)Classification of Wide Characters.
* iswpunct: (libc)Classification of Wide Characters.
* iswspace: (libc)Classification of Wide Characters.
* iswupper: (libc)Classification of Wide Characters.
* iswxdigit: (libc)Classification of Wide Characters.
* isxdigit: (libc)Classification of Characters.
* j0: (libc)Special Functions.
* j0f: (libc)Special Functions.
* j0l: (libc)Special Functions.
* j1: (libc)Special Functions.
* j1f: (libc)Special Functions.
* j1l: (libc)Special Functions.
* jn: (libc)Special Functions.
* jnf: (libc)Special Functions.
* jnl: (libc)Special Functions.
* jrand48: (libc)SVID Random.
* jrand48_r: (libc)SVID Random.
* kill: (libc)Signaling Another Process.
* killpg: (libc)Signaling Another Process.
* l64a: (libc)Encode Binary Data.
* labs: (libc)Absolute Value.
* lcong48: (libc)SVID Random.
* lcong48_r: (libc)SVID Random.
* ldexp: (libc)Normalization Functions.
* ldexpf: (libc)Normalization Functions.
* ldexpl: (libc)Normalization Functions.
* ldiv: (libc)Integer Division.
* lfind: (libc)Array Search Function.
* lgamma: (libc)Special Functions.
* lgamma_r: (libc)Special Functions.
* lgammaf: (libc)Special Functions.
* lgammaf_r: (libc)Special Functions.
* lgammal: (libc)Special Functions.
* lgammal_r: (libc)Special Functions.
* link: (libc)Hard Links.
* lio_listio64: (libc)Asynchronous Reads/Writes.
* lio_listio: (libc)Asynchronous Reads/Writes.
* listen: (libc)Listening.
* llabs: (libc)Absolute Value.
* lldiv: (libc)Integer Division.
* llrint: (libc)Rounding Functions.
* llrintf: (libc)Rounding Functions.
* llrintl: (libc)Rounding Functions.
* llround: (libc)Rounding Functions.
* llroundf: (libc)Rounding Functions.
* llroundl: (libc)Rounding Functions.
* localeconv: (libc)The Lame Way to Locale Data.
* localtime: (libc)Broken-down Time.
* localtime_r: (libc)Broken-down Time.
* log10: (libc)Exponents and Logarithms.
* log10f: (libc)Exponents and Logarithms.
* log10l: (libc)Exponents and Logarithms.
* log1p: (libc)Exponents and Logarithms.
* log1pf: (libc)Exponents and Logarithms.
* log1pl: (libc)Exponents and Logarithms.
* log2: (libc)Exponents and Logarithms.
* log2f: (libc)Exponents and Logarithms.
* log2l: (libc)Exponents and Logarithms.
* log: (libc)Exponents and Logarithms.
* logb: (libc)Exponents and Logarithms.
* logbf: (libc)Exponents and Logarithms.
* logbl: (libc)Exponents and Logarithms.
* logf: (libc)Exponents and Logarithms.
* login: (libc)Logging In and Out.
* login_tty: (libc)Logging In and Out.
* logl: (libc)Exponents and Logarithms.
* logout: (libc)Logging In and Out.
* logwtmp: (libc)Logging In and Out.
* longjmp: (libc)Non-Local Details.
* lrand48: (libc)SVID Random.
* lrand48_r: (libc)SVID Random.
* lrint: (libc)Rounding Functions.
* lrintf: (libc)Rounding Functions.
* lrintl: (libc)Rounding Functions.
* lround: (libc)Rounding Functions.
* lroundf: (libc)Rounding Functions.
* lroundl: (libc)Rounding Functions.
* lsearch: (libc)Array Search Function.
* lseek64: (libc)File Position Primitive.
* lseek: (libc)File Position Primitive.
* lstat64: (libc)Reading Attributes.
* lstat: (libc)Reading Attributes.
* lutimes: (libc)File Times.
* madvise: (libc)Memory-mapped I/O.
* makecontext: (libc)System V contexts.
* mallinfo: (libc)Statistics of Malloc.
* malloc: (libc)Basic Allocation.
* mallopt: (libc)Malloc Tunable Parameters.
* mblen: (libc)Non-reentrant Character Conversion.
* mbrlen: (libc)Converting a Character.
* mbrtowc: (libc)Converting a Character.
* mbsinit: (libc)Keeping the state.
* mbsnrtowcs: (libc)Converting Strings.
* mbsrtowcs: (libc)Converting Strings.
* mbstowcs: (libc)Non-reentrant String Conversion.
* mbtowc: (libc)Non-reentrant Character Conversion.
* mcheck: (libc)Heap Consistency Checking.
* memalign: (libc)Aligned Memory Blocks.
* memccpy: (libc)Copying and Concatenation.
* memchr: (libc)Search Functions.
* memcmp: (libc)String/Array Comparison.
* memcpy: (libc)Copying and Concatenation.
* memfrob: (libc)Trivial Encryption.
* memmem: (libc)Search Functions.
* memmove: (libc)Copying and Concatenation.
* mempcpy: (libc)Copying and Concatenation.
* memrchr: (libc)Search Functions.
* memset: (libc)Copying and Concatenation.
* mkdir: (libc)Creating Directories.
* mkdtemp: (libc)Temporary Files.
* mkfifo: (libc)FIFO Special Files.
* mknod: (libc)Making Special Files.
* mkstemp: (libc)Temporary Files.
* mktemp: (libc)Temporary Files.
* mktime: (libc)Broken-down Time.
* mlock: (libc)Page Lock Functions.
* mlockall: (libc)Page Lock Functions.
* mmap64: (libc)Memory-mapped I/O.
* mmap: (libc)Memory-mapped I/O.
* modf: (libc)Rounding Functions.
* modff: (libc)Rounding Functions.
* modfl: (libc)Rounding Functions.
* mount: (libc)Mount-Unmount-Remount.
* mprobe: (libc)Heap Consistency Checking.
* mrand48: (libc)SVID Random.
* mrand48_r: (libc)SVID Random.
* mremap: (libc)Memory-mapped I/O.
* msync: (libc)Memory-mapped I/O.
* mtrace: (libc)Tracing malloc.
* munlock: (libc)Page Lock Functions.
* munlockall: (libc)Page Lock Functions.
* munmap: (libc)Memory-mapped I/O.
* muntrace: (libc)Tracing malloc.
* nan: (libc)FP Bit Twiddling.
* nanf: (libc)FP Bit Twiddling.
* nanl: (libc)FP Bit Twiddling.
* nanosleep: (libc)Sleeping.
* nearbyint: (libc)Rounding Functions.
* nearbyintf: (libc)Rounding Functions.
* nearbyintl: (libc)Rounding Functions.
* nextafter: (libc)FP Bit Twiddling.
* nextafterf: (libc)FP Bit Twiddling.
* nextafterl: (libc)FP Bit Twiddling.
* nexttoward: (libc)FP Bit Twiddling.
* nexttowardf: (libc)FP Bit Twiddling.
* nexttowardl: (libc)FP Bit Twiddling.
* nftw64: (libc)Working with Directory Trees.
* nftw: (libc)Working with Directory Trees.
* ngettext: (libc)Advanced gettext functions.
* nice: (libc)Traditional Scheduling Functions.
* nl_langinfo: (libc)The Elegant and Fast Way.
* nrand48: (libc)SVID Random.
* nrand48_r: (libc)SVID Random.
* ntohl: (libc)Byte Order.
* ntohs: (libc)Byte Order.
* ntp_adjtime: (libc)High Accuracy Clock.
* ntp_gettime: (libc)High Accuracy Clock.
* obstack_1grow: (libc)Growing Objects.
* obstack_1grow_fast: (libc)Extra Fast Growing.
* obstack_alignment_mask: (libc)Obstacks Data Alignment.
* obstack_alloc: (libc)Allocation in an Obstack.
* obstack_base: (libc)Status of an Obstack.
* obstack_blank: (libc)Growing Objects.
* obstack_blank_fast: (libc)Extra Fast Growing.
* obstack_chunk_size: (libc)Obstack Chunks.
* obstack_copy0: (libc)Allocation in an Obstack.
* obstack_copy: (libc)Allocation in an Obstack.
* obstack_finish: (libc)Growing Objects.
* obstack_free: (libc)Freeing Obstack Objects.
* obstack_grow0: (libc)Growing Objects.
* obstack_grow: (libc)Growing Objects.
* obstack_init: (libc)Preparing for Obstacks.
* obstack_int_grow: (libc)Growing Objects.
* obstack_int_grow_fast: (libc)Extra Fast Growing.
* obstack_next_free: (libc)Status of an Obstack.
* obstack_object_size: (libc)Growing Objects.
* obstack_object_size: (libc)Status of an Obstack.
* obstack_printf: (libc)Dynamic Output.
* obstack_ptr_grow: (libc)Growing Objects.
* obstack_ptr_grow_fast: (libc)Extra Fast Growing.
* obstack_room: (libc)Extra Fast Growing.
* obstack_vprintf: (libc)Variable Arguments Output.
* offsetof: (libc)Structure Measurement.
* on_exit: (libc)Cleanups on Exit.
* open64: (libc)Opening and Closing Files.
* open: (libc)Opening and Closing Files.
* open_memstream: (libc)String Streams.
* open_obstack_stream: (libc)Obstack Streams.
* opendir: (libc)Opening a Directory.
* openlog: (libc)openlog.
* openpty: (libc)Pseudo-Terminal Pairs.
* parse_printf_format: (libc)Parsing a Template String.
* pathconf: (libc)Pathconf.
* pause: (libc)Using Pause.
* pclose: (libc)Pipe to a Subprocess.
* perror: (libc)Error Messages.
* pipe: (libc)Creating a Pipe.
* popen: (libc)Pipe to a Subprocess.
* posix_memalign: (libc)Aligned Memory Blocks.
* pow10: (libc)Exponents and Logarithms.
* pow10f: (libc)Exponents and Logarithms.
* pow10l: (libc)Exponents and Logarithms.
* pow: (libc)Exponents and Logarithms.
* powf: (libc)Exponents and Logarithms.
* powl: (libc)Exponents and Logarithms.
* pread64: (libc)I/O Primitives.
* pread: (libc)I/O Primitives.
* printf: (libc)Formatted Output Functions.
* printf_size: (libc)Predefined Printf Handlers.
* printf_size_info: (libc)Predefined Printf Handlers.
* psignal: (libc)Signal Messages.
* pthread_atfork: (libc)Threads and Fork.
* pthread_attr_destroy: (libc)Thread Attributes.
* pthread_attr_getattr: (libc)Thread Attributes.
* pthread_attr_init: (libc)Thread Attributes.
* pthread_attr_setattr: (libc)Thread Attributes.
* pthread_cancel: (libc)Basic Thread Operations.
* pthread_cleanup_pop: (libc)Cleanup Handlers.
* pthread_cleanup_pop_restore_np: (libc)Cleanup Handlers.
* pthread_cleanup_push: (libc)Cleanup Handlers.
* pthread_cleanup_push_defer_np: (libc)Cleanup Handlers.
* pthread_cond_broadcast: (libc)Condition Variables.
* pthread_cond_destroy: (libc)Condition Variables.
* pthread_cond_init: (libc)Condition Variables.
* pthread_cond_signal: (libc)Condition Variables.
* pthread_cond_timedwait: (libc)Condition Variables.
* pthread_cond_wait: (libc)Condition Variables.
* pthread_condattr_destroy: (libc)Condition Variables.
* pthread_condattr_init: (libc)Condition Variables.
* pthread_create: (libc)Basic Thread Operations.
* pthread_detach: (libc)Miscellaneous Thread Functions.
* pthread_equal: (libc)Miscellaneous Thread Functions.
* pthread_exit: (libc)Basic Thread Operations.
* pthread_getconcurrency: (libc)Miscellaneous Thread Functions.
* pthread_getschedparam: (libc)Miscellaneous Thread Functions.
* pthread_getspecific: (libc)Thread-Specific Data.
* pthread_join: (libc)Basic Thread Operations.
* pthread_key_create: (libc)Thread-Specific Data.
* pthread_key_delete: (libc)Thread-Specific Data.
* pthread_kill: (libc)Threads and Signal Handling.
* pthread_kill_other_threads_np: (libc)Miscellaneous Thread Functions.
* pthread_mutex_destroy: (libc)Mutexes.
* pthread_mutex_init: (libc)Mutexes.
* pthread_mutex_lock: (libc)Mutexes.
* pthread_mutex_timedlock: (libc)Mutexes.
* pthread_mutex_trylock: (libc)Mutexes.
* pthread_mutex_unlock: (libc)Mutexes.
* pthread_mutexattr_destroy: (libc)Mutexes.
* pthread_mutexattr_gettype: (libc)Mutexes.
* pthread_mutexattr_init: (libc)Mutexes.
* pthread_mutexattr_settype: (libc)Mutexes.
* pthread_once: (libc)Miscellaneous Thread Functions.
* pthread_self: (libc)Miscellaneous Thread Functions.
* pthread_setcancelstate: (libc)Cancellation.
* pthread_setcanceltype: (libc)Cancellation.
* pthread_setconcurrency: (libc)Miscellaneous Thread Functions.
* pthread_setschedparam: (libc)Miscellaneous Thread Functions.
* pthread_setspecific: (libc)Thread-Specific Data.
* pthread_sigmask: (libc)Threads and Signal Handling.
* pthread_testcancel: (libc)Cancellation.
* ptsname: (libc)Allocation.
* ptsname_r: (libc)Allocation.
* putc: (libc)Simple Output.
* putc_unlocked: (libc)Simple Output.
* putchar: (libc)Simple Output.
* putchar_unlocked: (libc)Simple Output.
* putenv: (libc)Environment Access.
* putpwent: (libc)Writing a User Entry.
* puts: (libc)Simple Output.
* pututline: (libc)Manipulating the Database.
* pututxline: (libc)XPG Functions.
* putw: (libc)Simple Output.
* putwc: (libc)Simple Output.
* putwc_unlocked: (libc)Simple Output.
* putwchar: (libc)Simple Output.
* putwchar_unlocked: (libc)Simple Output.
* pwrite64: (libc)I/O Primitives.
* pwrite: (libc)I/O Primitives.
* qecvt: (libc)System V Number Conversion.
* qecvt_r: (libc)System V Number Conversion.
* qfcvt: (libc)System V Number Conversion.
* qfcvt_r: (libc)System V Number Conversion.
* qgcvt: (libc)System V Number Conversion.
* qsort: (libc)Array Sort Function.
* raise: (libc)Signaling Yourself.
* rand: (libc)ISO Random.
* rand_r: (libc)ISO Random.
* random: (libc)BSD Random.
* random_r: (libc)BSD Random.
* rawmemchr: (libc)Search Functions.
* read: (libc)I/O Primitives.
* readdir64: (libc)Reading/Closing Directory.
* readdir64_r: (libc)Reading/Closing Directory.
* readdir: (libc)Reading/Closing Directory.
* readdir_r: (libc)Reading/Closing Directory.
* readlink: (libc)Symbolic Links.
* readv: (libc)Scatter-Gather.
* realloc: (libc)Changing Block Size.
* realpath: (libc)Symbolic Links.
* recv: (libc)Receiving Data.
* recvfrom: (libc)Receiving Datagrams.
* recvmsg: (libc)Receiving Datagrams.
* regcomp: (libc)POSIX Regexp Compilation.
* regerror: (libc)Regexp Cleanup.
* regexec: (libc)Matching POSIX Regexps.
* regfree: (libc)Regexp Cleanup.
* register_printf_function: (libc)Registering New Conversions.
* remainder: (libc)Remainder Functions.
* remainderf: (libc)Remainder Functions.
* remainderl: (libc)Remainder Functions.
* remove: (libc)Deleting Files.
* rename: (libc)Renaming Files.
* rewind: (libc)File Positioning.
* rewinddir: (libc)Random Access Directory.
* rindex: (libc)Search Functions.
* rint: (libc)Rounding Functions.
* rintf: (libc)Rounding Functions.
* rintl: (libc)Rounding Functions.
* rmdir: (libc)Deleting Files.
* round: (libc)Rounding Functions.
* roundf: (libc)Rounding Functions.
* roundl: (libc)Rounding Functions.
* rpmatch: (libc)Yes-or-No Questions.
* sbrk: (libc)Resizing the Data Segment.
* scalb: (libc)Normalization Functions.
* scalbf: (libc)Normalization Functions.
* scalbl: (libc)Normalization Functions.
* scalbln: (libc)Normalization Functions.
* scalblnf: (libc)Normalization Functions.
* scalblnl: (libc)Normalization Functions.
* scalbn: (libc)Normalization Functions.
* scalbnf: (libc)Normalization Functions.
* scalbnl: (libc)Normalization Functions.
* scandir64: (libc)Scanning Directory Content.
* scandir: (libc)Scanning Directory Content.
* scanf: (libc)Formatted Input Functions.
* sched_get_priority_max: (libc)Basic Scheduling Functions.
* sched_get_priority_min: (libc)Basic Scheduling Functions.
* sched_getaffinity: (libc)CPU Affinity.
* sched_getparam: (libc)Basic Scheduling Functions.
* sched_getscheduler: (libc)Basic Scheduling Functions.
* sched_rr_get_interval: (libc)Basic Scheduling Functions.
* sched_setaffinity: (libc)CPU Affinity.
* sched_setparam: (libc)Basic Scheduling Functions.
* sched_setscheduler: (libc)Basic Scheduling Functions.
* sched_yield: (libc)Basic Scheduling Functions.
* seed48: (libc)SVID Random.
* seed48_r: (libc)SVID Random.
* seekdir: (libc)Random Access Directory.
* select: (libc)Waiting for I/O.
* sem_destroy: (libc)POSIX Semaphores.
* sem_getvalue: (libc)POSIX Semaphores.
* sem_init: (libc)POSIX Semaphores.
* sem_post: (libc)POSIX Semaphores.
* sem_trywait: (libc)POSIX Semaphores.
* sem_wait: (libc)POSIX Semaphores.
* send: (libc)Sending Data.
* sendmsg: (libc)Receiving Datagrams.
* sendto: (libc)Sending Datagrams.
* setbuf: (libc)Controlling Buffering.
* setbuffer: (libc)Controlling Buffering.
* setcontext: (libc)System V contexts.
* setdomainname: (libc)Host Identification.
* setegid: (libc)Setting Groups.
* setenv: (libc)Environment Access.
* seteuid: (libc)Setting User ID.
* setfsent: (libc)fstab.
* setgid: (libc)Setting Groups.
* setgrent: (libc)Scanning All Groups.
* setgroups: (libc)Setting Groups.
* sethostent: (libc)Host Names.
* sethostid: (libc)Host Identification.
* sethostname: (libc)Host Identification.
* setitimer: (libc)Setting an Alarm.
* setjmp: (libc)Non-Local Details.
* setkey: (libc)DES Encryption.
* setkey_r: (libc)DES Encryption.
* setlinebuf: (libc)Controlling Buffering.
* setlocale: (libc)Setting the Locale.
* setlogmask: (libc)setlogmask.
* setmntent: (libc)mtab.
* setnetent: (libc)Networks Database.
* setnetgrent: (libc)Lookup Netgroup.
* setpgid: (libc)Process Group Functions.
* setpgrp: (libc)Process Group Functions.
* setpriority: (libc)Traditional Scheduling Functions.
* setprotoent: (libc)Protocols Database.
* setpwent: (libc)Scanning All Users.
* setregid: (libc)Setting Groups.
* setreuid: (libc)Setting User ID.
* setrlimit64: (libc)Limits on Resources.
* setrlimit: (libc)Limits on Resources.
* setservent: (libc)Services Database.
* setsid: (libc)Process Group Functions.
* setsockopt: (libc)Socket Option Functions.
* setstate: (libc)BSD Random.
* setstate_r: (libc)BSD Random.
* settimeofday: (libc)High-Resolution Calendar.
* setuid: (libc)Setting User ID.
* setutent: (libc)Manipulating the Database.
* setutxent: (libc)XPG Functions.
* setvbuf: (libc)Controlling Buffering.
* shutdown: (libc)Closing a Socket.
* sigaction: (libc)Advanced Signal Handling.
* sigaddset: (libc)Signal Sets.
* sigaltstack: (libc)Signal Stack.
* sigblock: (libc)Blocking in BSD.
* sigdelset: (libc)Signal Sets.
* sigemptyset: (libc)Signal Sets.
* sigfillset: (libc)Signal Sets.
* siginterrupt: (libc)BSD Handler.
* sigismember: (libc)Signal Sets.
* siglongjmp: (libc)Non-Local Exits and Signals.
* sigmask: (libc)Blocking in BSD.
* signal: (libc)Basic Signal Handling.
* signbit: (libc)FP Bit Twiddling.
* significand: (libc)Normalization Functions.
* significandf: (libc)Normalization Functions.
* significandl: (libc)Normalization Functions.
* sigpause: (libc)Blocking in BSD.
* sigpending: (libc)Checking for Pending Signals.
* sigprocmask: (libc)Process Signal Mask.
* sigsetjmp: (libc)Non-Local Exits and Signals.
* sigsetmask: (libc)Blocking in BSD.
* sigstack: (libc)Signal Stack.
* sigsuspend: (libc)Sigsuspend.
* sigvec: (libc)BSD Handler.
* sigwait: (libc)Threads and Signal Handling.
* sin: (libc)Trig Functions.
* sincos: (libc)Trig Functions.
* sincosf: (libc)Trig Functions.
* sincosl: (libc)Trig Functions.
* sinf: (libc)Trig Functions.
* sinh: (libc)Hyperbolic Functions.
* sinhf: (libc)Hyperbolic Functions.
* sinhl: (libc)Hyperbolic Functions.
* sinl: (libc)Trig Functions.
* sleep: (libc)Sleeping.
* snprintf: (libc)Formatted Output Functions.
* socket: (libc)Creating a Socket.
* socketpair: (libc)Socket Pairs.
* sprintf: (libc)Formatted Output Functions.
* sqrt: (libc)Exponents and Logarithms.
* sqrtf: (libc)Exponents and Logarithms.
* sqrtl: (libc)Exponents and Logarithms.
* srand48: (libc)SVID Random.
* srand48_r: (libc)SVID Random.
* srand: (libc)ISO Random.
* srandom: (libc)BSD Random.
* srandom_r: (libc)BSD Random.
* sscanf: (libc)Formatted Input Functions.
* ssignal: (libc)Basic Signal Handling.
* stat64: (libc)Reading Attributes.
* stat: (libc)Reading Attributes.
* stime: (libc)Simple Calendar Time.
* stpcpy: (libc)Copying and Concatenation.
* stpncpy: (libc)Copying and Concatenation.
* strcasecmp: (libc)String/Array Comparison.
* strcasestr: (libc)Search Functions.
* strcat: (libc)Copying and Concatenation.
* strchr: (libc)Search Functions.
* strchrnul: (libc)Search Functions.
* strcmp: (libc)String/Array Comparison.
* strcoll: (libc)Collation Functions.
* strcpy: (libc)Copying and Concatenation.
* strcspn: (libc)Search Functions.
* strdup: (libc)Copying and Concatenation.
* strdupa: (libc)Copying and Concatenation.
* strerror: (libc)Error Messages.
* strerror_r: (libc)Error Messages.
* strfmon: (libc)Formatting Numbers.
* strfry: (libc)strfry.
* strftime: (libc)Formatting Calendar Time.
* strlen: (libc)String Length.
* strncasecmp: (libc)String/Array Comparison.
* strncat: (libc)Copying and Concatenation.
* strncmp: (libc)String/Array Comparison.
* strncpy: (libc)Copying and Concatenation.
* strndup: (libc)Copying and Concatenation.
* strndupa: (libc)Copying and Concatenation.
* strnlen: (libc)String Length.
* strpbrk: (libc)Search Functions.
* strptime: (libc)Low-Level Time String Parsing.
* strrchr: (libc)Search Functions.
* strsep: (libc)Finding Tokens in a String.
* strsignal: (libc)Signal Messages.
* strspn: (libc)Search Functions.
* strstr: (libc)Search Functions.
* strtod: (libc)Parsing of Floats.
* strtof: (libc)Parsing of Floats.
* strtoimax: (libc)Parsing of Integers.
* strtok: (libc)Finding Tokens in a String.
* strtok_r: (libc)Finding Tokens in a String.
* strtol: (libc)Parsing of Integers.
* strtold: (libc)Parsing of Floats.
* strtoll: (libc)Parsing of Integers.
* strtoq: (libc)Parsing of Integers.
* strtoul: (libc)Parsing of Integers.
* strtoull: (libc)Parsing of Integers.
* strtoumax: (libc)Parsing of Integers.
* strtouq: (libc)Parsing of Integers.
* strverscmp: (libc)String/Array Comparison.
* strxfrm: (libc)Collation Functions.
* stty: (libc)BSD Terminal Modes.
* swapcontext: (libc)System V contexts.
* swprintf: (libc)Formatted Output Functions.
* swscanf: (libc)Formatted Input Functions.
* symlink: (libc)Symbolic Links.
* sync: (libc)Synchronizing I/O.
* syscall: (libc)System Calls.
* sysconf: (libc)Sysconf Definition.
* sysctl: (libc)System Parameters.
* syslog: (libc)syslog; vsyslog.
* system: (libc)Running a Command.
* sysv_signal: (libc)Basic Signal Handling.
* tan: (libc)Trig Functions.
* tanf: (libc)Trig Functions.
* tanh: (libc)Hyperbolic Functions.
* tanhf: (libc)Hyperbolic Functions.
* tanhl: (libc)Hyperbolic Functions.
* tanl: (libc)Trig Functions.
* tcdrain: (libc)Line Control.
* tcflow: (libc)Line Control.
* tcflush: (libc)Line Control.
* tcgetattr: (libc)Mode Functions.
* tcgetpgrp: (libc)Terminal Access Functions.
* tcgetsid: (libc)Terminal Access Functions.
* tcsendbreak: (libc)Line Control.
* tcsetattr: (libc)Mode Functions.
* tcsetpgrp: (libc)Terminal Access Functions.
* tdelete: (libc)Tree Search Function.
* tdestroy: (libc)Tree Search Function.
* telldir: (libc)Random Access Directory.
* tempnam: (libc)Temporary Files.
* textdomain: (libc)Locating gettext catalog.
* tfind: (libc)Tree Search Function.
* tgamma: (libc)Special Functions.
* tgammaf: (libc)Special Functions.
* tgammal: (libc)Special Functions.
* time: (libc)Simple Calendar Time.
* timegm: (libc)Broken-down Time.
* timelocal: (libc)Broken-down Time.
* times: (libc)Processor Time.
* tmpfile64: (libc)Temporary Files.
* tmpfile: (libc)Temporary Files.
* tmpnam: (libc)Temporary Files.
* tmpnam_r: (libc)Temporary Files.
* toascii: (libc)Case Conversion.
* tolower: (libc)Case Conversion.
* toupper: (libc)Case Conversion.
* towctrans: (libc)Wide Character Case Conversion.
* towlower: (libc)Wide Character Case Conversion.
* towupper: (libc)Wide Character Case Conversion.
* trunc: (libc)Rounding Functions.
* truncate64: (libc)File Size.
* truncate: (libc)File Size.
* truncf: (libc)Rounding Functions.
* truncl: (libc)Rounding Functions.
* tsearch: (libc)Tree Search Function.
* ttyname: (libc)Is It a Terminal.
* ttyname_r: (libc)Is It a Terminal.
* twalk: (libc)Tree Search Function.
* tzset: (libc)Time Zone Functions.
* ulimit: (libc)Limits on Resources.
* umask: (libc)Setting Permissions.
* umount2: (libc)Mount-Unmount-Remount.
* umount: (libc)Mount-Unmount-Remount.
* uname: (libc)Platform Type.
* ungetc: (libc)How Unread.
* ungetwc: (libc)How Unread.
* unlink: (libc)Deleting Files.
* unlockpt: (libc)Allocation.
* unsetenv: (libc)Environment Access.
* updwtmp: (libc)Manipulating the Database.
* utime: (libc)File Times.
* utimes: (libc)File Times.
* utmpname: (libc)Manipulating the Database.
* utmpxname: (libc)XPG Functions.
* va_arg: (libc)Argument Macros.
* va_end: (libc)Argument Macros.
* va_start: (libc)Argument Macros.
* va_start: (libc)Old Varargs.
* valloc: (libc)Aligned Memory Blocks.
* vasprintf: (libc)Variable Arguments Output.
* verr: (libc)Error Messages.
* verrx: (libc)Error Messages.
* versionsort64: (libc)Scanning Directory Content.
* versionsort: (libc)Scanning Directory Content.
* vfork: (libc)Creating a Process.
* vfprintf: (libc)Variable Arguments Output.
* vfscanf: (libc)Variable Arguments Input.
* vfwprintf: (libc)Variable Arguments Output.
* vfwscanf: (libc)Variable Arguments Input.
* vlimit: (libc)Limits on Resources.
* vprintf: (libc)Variable Arguments Output.
* vscanf: (libc)Variable Arguments Input.
* vsnprintf: (libc)Variable Arguments Output.
* vsprintf: (libc)Variable Arguments Output.
* vsscanf: (libc)Variable Arguments Input.
* vswprintf: (libc)Variable Arguments Output.
* vswscanf: (libc)Variable Arguments Input.
* vsyslog: (libc)syslog; vsyslog.
* vtimes: (libc)Resource Usage.
* vwarn: (libc)Error Messages.
* vwarnx: (libc)Error Messages.
* vwprintf: (libc)Variable Arguments Output.
* vwscanf: (libc)Variable Arguments Input.
* wait3: (libc)BSD Wait Functions.
* wait4: (libc)Process Completion.
* wait: (libc)Process Completion.
* waitpid: (libc)Process Completion.
* warn: (libc)Error Messages.
* warnx: (libc)Error Messages.
* wcpcpy: (libc)Copying and Concatenation.
* wcpncpy: (libc)Copying and Concatenation.
* wcrtomb: (libc)Converting a Character.
* wcscasecmp: (libc)String/Array Comparison.
* wcscat: (libc)Copying and Concatenation.
* wcschr: (libc)Search Functions.
* wcschrnul: (libc)Search Functions.
* wcscmp: (libc)String/Array Comparison.
* wcscoll: (libc)Collation Functions.
* wcscpy: (libc)Copying and Concatenation.
* wcscspn: (libc)Search Functions.
* wcsdup: (libc)Copying and Concatenation.
* wcsftime: (libc)Formatting Calendar Time.
* wcslen: (libc)String Length.
* wcsncasecmp: (libc)String/Array Comparison.
* wcsncat: (libc)Copying and Concatenation.
* wcsncmp: (libc)String/Array Comparison.
* wcsncpy: (libc)Copying and Concatenation.
* wcsnlen: (libc)String Length.
* wcsnrtombs: (libc)Converting Strings.
* wcspbrk: (libc)Search Functions.
* wcsrchr: (libc)Search Functions.
* wcsrtombs: (libc)Converting Strings.
* wcsspn: (libc)Search Functions.
* wcsstr: (libc)Search Functions.
* wcstod: (libc)Parsing of Floats.
* wcstof: (libc)Parsing of Floats.
* wcstoimax: (libc)Parsing of Integers.
* wcstok: (libc)Finding Tokens in a String.
* wcstol: (libc)Parsing of Integers.
* wcstold: (libc)Parsing of Floats.
* wcstoll: (libc)Parsing of Integers.
* wcstombs: (libc)Non-reentrant String Conversion.
* wcstoq: (libc)Parsing of Integers.
* wcstoul: (libc)Parsing of Integers.
* wcstoull: (libc)Parsing of Integers.
* wcstoumax: (libc)Parsing of Integers.
* wcstouq: (libc)Parsing of Integers.
* wcswcs: (libc)Search Functions.
* wcsxfrm: (libc)Collation Functions.
* wctob: (libc)Converting a Character.
* wctomb: (libc)Non-reentrant Character Conversion.
* wctrans: (libc)Wide Character Case Conversion.
* wctype: (libc)Classification of Wide Characters.
* wmemchr: (libc)Search Functions.
* wmemcmp: (libc)String/Array Comparison.
* wmemcpy: (libc)Copying and Concatenation.
* wmemmove: (libc)Copying and Concatenation.
* wmempcpy: (libc)Copying and Concatenation.
* wmemset: (libc)Copying and Concatenation.
* wordexp: (libc)Calling Wordexp.
* wordfree: (libc)Calling Wordexp.
* wprintf: (libc)Formatted Output Functions.
* write: (libc)I/O Primitives.
* writev: (libc)Scatter-Gather.
* wscanf: (libc)Formatted Input Functions.
* y0: (libc)Special Functions.
* y0f: (libc)Special Functions.
* y0l: (libc)Special Functions.
* y1: (libc)Special Functions.
* y1f: (libc)Special Functions.
* y1l: (libc)Special Functions.
* yn: (libc)Special Functions.
* ynf: (libc)Special Functions.
* ynl: (libc)Special Functions.
END-INFO-DIR-ENTRY

   This file documents the GNU C library.

   This is Edition 0.10, last updated 2001-07-06, of `The GNU C Library
Reference Manual', for Version 2.3.x.

   Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002,
2003 Free Software Foundation, Inc.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Free Software Needs Free Documentation" and
"GNU Lesser General Public License", the Front-Cover texts being (a)
(see below), and with the Back-Cover Texts being (b) (see below).  A
copy of the license is included in the section entitled "GNU Free
Documentation License".

   (a) The FSF's Front-Cover Text is:

   A GNU Manual

   (b) The FSF's Back-Cover Text is:

   You have freedom to copy and modify this GNU Manual, like GNU
software.  Copies published by the Free Software Foundation raise
funds for GNU development.


File: libc.info,  Node: Constants for Sysconf,  Next: Examples of Sysconf,  Prev: Sysconf Definition,  Up: Sysconf

Constants for `sysconf' Parameters
----------------------------------

   Here are the symbolic constants for use as the PARAMETER argument to
`sysconf'.  The values are all integer constants (more specifically,
enumeration type values).

`_SC_ARG_MAX'
     Inquire about the parameter corresponding to `ARG_MAX'.

`_SC_CHILD_MAX'
     Inquire about the parameter corresponding to `CHILD_MAX'.

`_SC_OPEN_MAX'
     Inquire about the parameter corresponding to `OPEN_MAX'.

`_SC_STREAM_MAX'
     Inquire about the parameter corresponding to `STREAM_MAX'.

`_SC_TZNAME_MAX'
     Inquire about the parameter corresponding to `TZNAME_MAX'.

`_SC_NGROUPS_MAX'
     Inquire about the parameter corresponding to `NGROUPS_MAX'.

`_SC_JOB_CONTROL'
     Inquire about the parameter corresponding to `_POSIX_JOB_CONTROL'.

`_SC_SAVED_IDS'
     Inquire about the parameter corresponding to `_POSIX_SAVED_IDS'.

`_SC_VERSION'
     Inquire about the parameter corresponding to `_POSIX_VERSION'.

`_SC_CLK_TCK'
     Inquire about the parameter corresponding to `CLOCKS_PER_SEC';
     *note CPU Time::.

`_SC_CHARCLASS_NAME_MAX'
     Inquire about the parameter corresponding to maximal length
     allowed for a character class name in an extended locale
     specification.  These extensions are not yet standardized and so
     this option is not standardized as well.

`_SC_REALTIME_SIGNALS'
     Inquire about the parameter corresponding to
     `_POSIX_REALTIME_SIGNALS'.

`_SC_PRIORITY_SCHEDULING'
     Inquire about the parameter corresponding to
     `_POSIX_PRIORITY_SCHEDULING'.

`_SC_TIMERS'
     Inquire about the parameter corresponding to `_POSIX_TIMERS'.

`_SC_ASYNCHRONOUS_IO'
     Inquire about the parameter corresponding to
     `_POSIX_ASYNCHRONOUS_IO'.

`_SC_PRIORITIZED_IO'
     Inquire about the parameter corresponding to
     `_POSIX_PRIORITIZED_IO'.

`_SC_SYNCHRONIZED_IO'
     Inquire about the parameter corresponding to
     `_POSIX_SYNCHRONIZED_IO'.

`_SC_FSYNC'
     Inquire about the parameter corresponding to `_POSIX_FSYNC'.

`_SC_MAPPED_FILES'
     Inquire about the parameter corresponding to `_POSIX_MAPPED_FILES'.

`_SC_MEMLOCK'
     Inquire about the parameter corresponding to `_POSIX_MEMLOCK'.

`_SC_MEMLOCK_RANGE'
     Inquire about the parameter corresponding to
     `_POSIX_MEMLOCK_RANGE'.

`_SC_MEMORY_PROTECTION'
     Inquire about the parameter corresponding to
     `_POSIX_MEMORY_PROTECTION'.

`_SC_MESSAGE_PASSING'
     Inquire about the parameter corresponding to
     `_POSIX_MESSAGE_PASSING'.

`_SC_SEMAPHORES'
     Inquire about the parameter corresponding to `_POSIX_SEMAPHORES'.

`_SC_SHARED_MEMORY_OBJECTS'
     Inquire about the parameter corresponding to
     `_POSIX_SHARED_MEMORY_OBJECTS'.

`_SC_AIO_LISTIO_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_AIO_LISTIO_MAX'.

`_SC_AIO_MAX'
     Inquire about the parameter corresponding to `_POSIX_AIO_MAX'.

`_SC_AIO_PRIO_DELTA_MAX'
     Inquire the value by which a process can decrease its asynchronous
     I/O priority level from its own scheduling priority.  This
     corresponds to the run-time invariant value `AIO_PRIO_DELTA_MAX'.

`_SC_DELAYTIMER_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_DELAYTIMER_MAX'.

`_SC_MQ_OPEN_MAX'
     Inquire about the parameter corresponding to `_POSIX_MQ_OPEN_MAX'.

`_SC_MQ_PRIO_MAX'
     Inquire about the parameter corresponding to `_POSIX_MQ_PRIO_MAX'.

`_SC_RTSIG_MAX'
     Inquire about the parameter corresponding to `_POSIX_RTSIG_MAX'.

`_SC_SEM_NSEMS_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_SEM_NSEMS_MAX'.

`_SC_SEM_VALUE_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_SEM_VALUE_MAX'.

`_SC_SIGQUEUE_MAX'
     Inquire about the parameter corresponding to `_POSIX_SIGQUEUE_MAX'.

`_SC_TIMER_MAX'
     Inquire about the parameter corresponding to `_POSIX_TIMER_MAX'.

`_SC_PII'
     Inquire about the parameter corresponding to `_POSIX_PII'.

`_SC_PII_XTI'
     Inquire about the parameter corresponding to `_POSIX_PII_XTI'.

`_SC_PII_SOCKET'
     Inquire about the parameter corresponding to `_POSIX_PII_SOCKET'.

`_SC_PII_INTERNET'
     Inquire about the parameter corresponding to `_POSIX_PII_INTERNET'.

`_SC_PII_OSI'
     Inquire about the parameter corresponding to `_POSIX_PII_OSI'.

`_SC_SELECT'
     Inquire about the parameter corresponding to `_POSIX_SELECT'.

`_SC_UIO_MAXIOV'
     Inquire about the parameter corresponding to `_POSIX_UIO_MAXIOV'.

`_SC_PII_INTERNET_STREAM'
     Inquire about the parameter corresponding to
     `_POSIX_PII_INTERNET_STREAM'.

`_SC_PII_INTERNET_DGRAM'
     Inquire about the parameter corresponding to
     `_POSIX_PII_INTERNET_DGRAM'.

`_SC_PII_OSI_COTS'
     Inquire about the parameter corresponding to `_POSIX_PII_OSI_COTS'.

`_SC_PII_OSI_CLTS'
     Inquire about the parameter corresponding to `_POSIX_PII_OSI_CLTS'.

`_SC_PII_OSI_M'
     Inquire about the parameter corresponding to `_POSIX_PII_OSI_M'.

`_SC_T_IOV_MAX'
     Inquire the value of the value associated with the `T_IOV_MAX'
     variable.

`_SC_THREADS'
     Inquire about the parameter corresponding to `_POSIX_THREADS'.

`_SC_THREAD_SAFE_FUNCTIONS'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_SAFE_FUNCTIONS'.

`_SC_GETGR_R_SIZE_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_GETGR_R_SIZE_MAX'.

`_SC_GETPW_R_SIZE_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_GETPW_R_SIZE_MAX'.

`_SC_LOGIN_NAME_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_LOGIN_NAME_MAX'.

`_SC_TTY_NAME_MAX'
     Inquire about the parameter corresponding to `_POSIX_TTY_NAME_MAX'.

`_SC_THREAD_DESTRUCTOR_ITERATIONS'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_DESTRUCTOR_ITERATIONS'.

`_SC_THREAD_KEYS_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_KEYS_MAX'.

`_SC_THREAD_STACK_MIN'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_STACK_MIN'.

`_SC_THREAD_THREADS_MAX'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_THREADS_MAX'.

`_SC_THREAD_ATTR_STACKADDR'
     Inquire about the parameter corresponding to
     a `_POSIX_THREAD_ATTR_STACKADDR'.

`_SC_THREAD_ATTR_STACKSIZE'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_ATTR_STACKSIZE'.

`_SC_THREAD_PRIORITY_SCHEDULING'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_PRIORITY_SCHEDULING'.

`_SC_THREAD_PRIO_INHERIT'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_PRIO_INHERIT'.

`_SC_THREAD_PRIO_PROTECT'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_PRIO_PROTECT'.

`_SC_THREAD_PROCESS_SHARED'
     Inquire about the parameter corresponding to
     `_POSIX_THREAD_PROCESS_SHARED'.

`_SC_2_C_DEV'
     Inquire about whether the system has the POSIX.2 C compiler
     command, `c89'.

`_SC_2_FORT_DEV'
     Inquire about whether the system has the POSIX.2 Fortran compiler
     command, `fort77'.

`_SC_2_FORT_RUN'
     Inquire about whether the system has the POSIX.2 `asa' command to
     interpret Fortran carriage control.

`_SC_2_LOCALEDEF'
     Inquire about whether the system has the POSIX.2 `localedef'
     command.

`_SC_2_SW_DEV'
     Inquire about whether the system has the POSIX.2 commands `ar',
     `make', and `strip'.

`_SC_BC_BASE_MAX'
     Inquire about the maximum value of `obase' in the `bc' utility.

`_SC_BC_DIM_MAX'
     Inquire about the maximum size of an array in the `bc' utility.

`_SC_BC_SCALE_MAX'
     Inquire about the maximum value of `scale' in the `bc' utility.

`_SC_BC_STRING_MAX'
     Inquire about the maximum size of a string constant in the `bc'
     utility.

`_SC_COLL_WEIGHTS_MAX'
     Inquire about the maximum number of weights that can necessarily
     be used in defining the collating sequence for a locale.

`_SC_EXPR_NEST_MAX'
     Inquire about the maximum number of expressions nested within
     parentheses when using the `expr' utility.

`_SC_LINE_MAX'
     Inquire about the maximum size of a text line that the POSIX.2 text
     utilities can handle.

`_SC_EQUIV_CLASS_MAX'
     Inquire about the maximum number of weights that can be assigned
     to an entry of the `LC_COLLATE' category `order' keyword in a
     locale definition.  The GNU C library does not presently support
     locale definitions.

`_SC_VERSION'
     Inquire about the version number of POSIX.1 that the library and
     kernel support.

`_SC_2_VERSION'
     Inquire about the version number of POSIX.2 that the system
     utilities support.

`_SC_PAGESIZE'
     Inquire about the virtual memory page size of the machine.
     `getpagesize' returns the same value (*note Query Memory
     Parameters::).

`_SC_NPROCESSORS_CONF'
     Inquire about the number of configured processors.

`_SC_NPROCESSORS_ONLN'
     Inquire about the number of processors online.

`_SC_PHYS_PAGES'
     Inquire about the number of physical pages in the system.

`_SC_AVPHYS_PAGES'
     Inquire about the number of available physical pages in the system.

`_SC_ATEXIT_MAX'
     Inquire about the number of functions which can be registered as
     termination functions for `atexit'; *note Cleanups on Exit::.

`_SC_XOPEN_VERSION'
     Inquire about the parameter corresponding to `_XOPEN_VERSION'.

`_SC_XOPEN_XCU_VERSION'
     Inquire about the parameter corresponding to `_XOPEN_XCU_VERSION'.

`_SC_XOPEN_UNIX'
     Inquire about the parameter corresponding to `_XOPEN_UNIX'.

`_SC_XOPEN_REALTIME'
     Inquire about the parameter corresponding to `_XOPEN_REALTIME'.

`_SC_XOPEN_REALTIME_THREADS'
     Inquire about the parameter corresponding to
     `_XOPEN_REALTIME_THREADS'.

`_SC_XOPEN_LEGACY'
     Inquire about the parameter corresponding to `_XOPEN_LEGACY'.

`_SC_XOPEN_CRYPT'
     Inquire about the parameter corresponding to `_XOPEN_CRYPT'.

`_SC_XOPEN_ENH_I18N'
     Inquire about the parameter corresponding to `_XOPEN_ENH_I18N'.

`_SC_XOPEN_SHM'
     Inquire about the parameter corresponding to `_XOPEN_SHM'.

`_SC_XOPEN_XPG2'
     Inquire about the parameter corresponding to `_XOPEN_XPG2'.

`_SC_XOPEN_XPG3'
     Inquire about the parameter corresponding to `_XOPEN_XPG3'.

`_SC_XOPEN_XPG4'
     Inquire about the parameter corresponding to `_XOPEN_XPG4'.

`_SC_CHAR_BIT'
     Inquire about the number of bits in a variable of type `char'.

`_SC_CHAR_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `char'.

`_SC_CHAR_MIN'
     Inquire about the minimum value which can be stored in a variable
     of type `char'.

`_SC_INT_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `int'.

`_SC_INT_MIN'
     Inquire about the minimum value which can be stored in a variable
     of type `int'.

`_SC_LONG_BIT'
     Inquire about the number of bits in a variable of type `long int'.

`_SC_WORD_BIT'
     Inquire about the number of bits in a variable of a register word.

`_SC_MB_LEN_MAX'
     Inquire the maximum length of a multi-byte representation of a wide
     character value.

`_SC_NZERO'
     Inquire about the value used to internally represent the zero
     priority level for the process execution.

`SC_SSIZE_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `ssize_t'.

`_SC_SCHAR_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `signed char'.

`_SC_SCHAR_MIN'
     Inquire about the minimum value which can be stored in a variable
     of type `signed char'.

`_SC_SHRT_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `short int'.

`_SC_SHRT_MIN'
     Inquire about the minimum value which can be stored in a variable
     of type `short int'.

`_SC_UCHAR_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `unsigned char'.

`_SC_UINT_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `unsigned int'.

`_SC_ULONG_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `unsigned long int'.

`_SC_USHRT_MAX'
     Inquire about the maximum value which can be stored in a variable
     of type `unsigned short int'.

`_SC_NL_ARGMAX'
     Inquire about the parameter corresponding to `NL_ARGMAX'.

`_SC_NL_LANGMAX'
     Inquire about the parameter corresponding to `NL_LANGMAX'.

`_SC_NL_MSGMAX'
     Inquire about the parameter corresponding to `NL_MSGMAX'.

`_SC_NL_NMAX'
     Inquire about  the parameter corresponding to `NL_NMAX'.

`_SC_NL_SETMAX'
     Inquire about the parameter corresponding to `NL_SETMAX'.

`_SC_NL_TEXTMAX'
     Inquire about the parameter corresponding to `NL_TEXTMAX'.


File: libc.info,  Node: Examples of Sysconf,  Prev: Constants for Sysconf,  Up: Sysconf

Examples of `sysconf'
---------------------

   We recommend that you first test for a macro definition for the
parameter you are interested in, and call `sysconf' only if the macro
is not defined.  For example, here is how to test whether job control
is supported:

     int
     have_job_control (void)
     {
     #ifdef _POSIX_JOB_CONTROL
       return 1;
     #else
       int value = sysconf (_SC_JOB_CONTROL);
       if (value < 0)
         /* If the system is that badly wedged,
            there's no use trying to go on.  */
         fatal (strerror (errno));
       return value;
     #endif
     }

   Here is how to get the value of a numeric limit:

     int
     get_child_max ()
     {
     #ifdef CHILD_MAX
       return CHILD_MAX;
     #else
       int value = sysconf (_SC_CHILD_MAX);
       if (value < 0)
         fatal (strerror (errno));
       return value;
     #endif
     }


File: libc.info,  Node: Minimums,  Next: Limits for Files,  Prev: Sysconf,  Up: System Configuration

Minimum Values for General Capacity Limits
==========================================

   Here are the names for the POSIX minimum upper bounds for the system
limit parameters.  The significance of these values is that you can
safely push to these limits without checking whether the particular
system you are using can go that far.

`_POSIX_AIO_LISTIO_MAX'
     The most restrictive limit permitted by POSIX for the maximum
     number of I/O operations that can be specified in a list I/O call.
     The value of this constant is `2'; thus you can add up to two new
     entries of the list of outstanding operations.

`_POSIX_AIO_MAX'
     The most restrictive limit permitted by POSIX for the maximum
     number of outstanding asynchronous I/O operations.  The value of
     this constant is `1'.  So you cannot expect that you can issue
     more than one operation and immediately continue with the normal
     work, receiving the notifications asynchronously.

`_POSIX_ARG_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum combined length of the ARGV and ENVIRON
     arguments that can be passed to the `exec' functions.  Its value
     is `4096'.

`_POSIX_CHILD_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum number of simultaneous processes per real
     user ID.  Its value is `6'.

`_POSIX_NGROUPS_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum number of supplementary group IDs per
     process.  Its value is `0'.

`_POSIX_OPEN_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum number of files that a single process can
     have open simultaneously.  Its value is `16'.

`_POSIX_SSIZE_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum value that can be stored in an object of type
     `ssize_t'.  Its value is `32767'.

`_POSIX_STREAM_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum number of streams that a single process can
     have open simultaneously.  Its value is `8'.

`_POSIX_TZNAME_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the maximum length of a time zone name.  Its value is
     `3'.

`_POSIX2_RE_DUP_MAX'
     The value of this macro is the most restrictive limit permitted by
     POSIX for the numbers used in the `\{MIN,MAX\}' construct in a
     regular expression.  Its value is `255'.


File: libc.info,  Node: Limits for Files,  Next: Options for Files,  Prev: Minimums,  Up: System Configuration

Limits on File System Capacity
==============================

   The POSIX.1 standard specifies a number of parameters that describe
the limitations of the file system.  It's possible for the system to
have a fixed, uniform limit for a parameter, but this isn't the usual
case.  On most systems, it's possible for different file systems (and,
for some parameters, even different files) to have different maximum
limits.  For example, this is very likely if you use NFS to mount some
of the file systems from other machines.

   Each of the following macros is defined in `limits.h' only if the
system has a fixed, uniform limit for the parameter in question.  If the
system allows different file systems or files to have different limits,
then the macro is undefined; use `pathconf' or `fpathconf' to find out
the limit that applies to a particular file.  *Note Pathconf::.

   Each parameter also has another macro, with a name starting with
`_POSIX', which gives the lowest value that the limit is allowed to
have on _any_ POSIX system.  *Note File Minimums::.

 - Macro: int LINK_MAX
     The uniform system limit (if any) for the number of names for a
     given file.  *Note Hard Links::.

 - Macro: int MAX_CANON
     The uniform system limit (if any) for the amount of text in a line
     of input when input editing is enabled.  *Note Canonical or Not::.

 - Macro: int MAX_INPUT
     The uniform system limit (if any) for the total number of
     characters typed ahead as input.  *Note I/O Queues::.

 - Macro: int NAME_MAX
     The uniform system limit (if any) for the length of a file name
     component.

 - Macro: int PATH_MAX
     The uniform system limit (if any) for the length of an entire file
     name (that is, the argument given to system calls such as `open').

 - Macro: int PIPE_BUF
     The uniform system limit (if any) for the number of bytes that can
     be written atomically to a pipe.  If multiple processes are
     writing to the same pipe simultaneously, output from different
     processes might be interleaved in chunks of this size.  *Note
     Pipes and FIFOs::.

   These are alternative macro names for some of the same information.

 - Macro: int MAXNAMLEN
     This is the BSD name for `NAME_MAX'.  It is defined in `dirent.h'.

 - Macro: int FILENAME_MAX
     The value of this macro is an integer constant expression that
     represents the maximum length of a file name string.  It is
     defined in `stdio.h'.

     Unlike `PATH_MAX', this macro is defined even if there is no actual
     limit imposed.  In such a case, its value is typically a very large
     number.  *This is always the case on the GNU system.*

     *Usage Note:* Don't use `FILENAME_MAX' as the size of an array in
     which to store a file name!  You can't possibly make an array that
     big!  Use dynamic allocation (*note Memory Allocation::) instead.


File: libc.info,  Node: Options for Files,  Next: File Minimums,  Prev: Limits for Files,  Up: System Configuration

Optional Features in File Support
=================================

   POSIX defines certain system-specific options in the system calls for
operating on files.  Some systems support these options and others do
not.  Since these options are provided in the kernel, not in the
library, simply using the GNU C library does not guarantee that any of
these features is supported; it depends on the system you are using.
They can also vary between file systems on a single machine.

   This section describes the macros you can test to determine whether a
particular option is supported on your machine.  If a given macro is
defined in `unistd.h', then its value says whether the corresponding
feature is supported.  (A value of `-1' indicates no; any other value
indicates yes.)  If the macro is undefined, it means particular files
may or may not support the feature.

   Since all the machines that support the GNU C library also support
NFS, one can never make a general statement about whether all file
systems support the `_POSIX_CHOWN_RESTRICTED' and `_POSIX_NO_TRUNC'
features.  So these names are never defined as macros in the GNU C
library.

 - Macro: int _POSIX_CHOWN_RESTRICTED
     If this option is in effect, the `chown' function is restricted so
     that the only changes permitted to nonprivileged processes is to
     change the group owner of a file to either be the effective group
     ID of the process, or one of its supplementary group IDs.  *Note
     File Owner::.

 - Macro: int _POSIX_NO_TRUNC
     If this option is in effect, file name components longer than
     `NAME_MAX' generate an `ENAMETOOLONG' error.  Otherwise, file name
     components that are too long are silently truncated.

 - Macro: unsigned char _POSIX_VDISABLE
     This option is only meaningful for files that are terminal devices.
     If it is enabled, then handling for special control characters can
     be disabled individually.  *Note Special Characters::.

   If one of these macros is undefined, that means that the option
might be in effect for some files and not for others.  To inquire about
a particular file, call `pathconf' or `fpathconf'.  *Note Pathconf::.


File: libc.info,  Node: File Minimums,  Next: Pathconf,  Prev: Options for Files,  Up: System Configuration

Minimum Values for File System Limits
=====================================

   Here are the names for the POSIX minimum upper bounds for some of the
above parameters.  The significance of these values is that you can
safely push to these limits without checking whether the particular
system you are using can go that far.  In most cases GNU systems do not
have these strict limitations.  The actual limit should be requested if
necessary.

`_POSIX_LINK_MAX'
     The most restrictive limit permitted by POSIX for the maximum
     value of a file's link count.  The value of this constant is `8';
     thus, you can always make up to eight names for a file without
     running into a system limit.

`_POSIX_MAX_CANON'
     The most restrictive limit permitted by POSIX for the maximum
     number of bytes in a canonical input line from a terminal device.
     The value of this constant is `255'.

`_POSIX_MAX_INPUT'
     The most restrictive limit permitted by POSIX for the maximum
     number of bytes in a terminal device input queue (or typeahead
     buffer).  *Note Input Modes::.  The value of this constant is
     `255'.

`_POSIX_NAME_MAX'
     The most restrictive limit permitted by POSIX for the maximum
     number of bytes in a file name component.  The value of this
     constant is `14'.

`_POSIX_PATH_MAX'
     The most restrictive limit permitted by POSIX for the maximum
     number of bytes in a file name.  The value of this constant is
     `256'.

`_POSIX_PIPE_BUF'
     The most restrictive limit permitted by POSIX for the maximum
     number of bytes that can be written atomically to a pipe.  The
     value of this constant is `512'.

`SYMLINK_MAX'
     Maximum number of bytes in a symbolic link.

`POSIX_REC_INCR_XFER_SIZE'
     Recommended increment for file transfer sizes between the
     `POSIX_REC_MIN_XFER_SIZE' and `POSIX_REC_MAX_XFER_SIZE' values.

`POSIX_REC_MAX_XFER_SIZE'
     Maximum recommended file transfer size.

`POSIX_REC_MIN_XFER_SIZE'
     Minimum recommended file transfer size.

`POSIX_REC_XFER_ALIGN'
     Recommended file transfer buffer alignment.


File: libc.info,  Node: Pathconf,  Next: Utility Limits,  Prev: File Minimums,  Up: System Configuration

Using `pathconf'
================

   When your machine allows different files to have different values
for a file system parameter, you can use the functions in this section
to find out the value that applies to any particular file.

   These functions and the associated constants for the PARAMETER
argument are declared in the header file `unistd.h'.

 - Function: long int pathconf (const char *FILENAME, int PARAMETER)
     This function is used to inquire about the limits that apply to
     the file named FILENAME.

     The PARAMETER argument should be one of the `_PC_' constants
     listed below.

     The normal return value from `pathconf' is the value you requested.
     A value of `-1' is returned both if the implementation does not
     impose a limit, and in case of an error.  In the former case,
     `errno' is not set, while in the latter case, `errno' is set to
     indicate the cause of the problem.  So the only way to use this
     function robustly is to store `0' into `errno' just before calling
     it.

     Besides the usual file name errors (*note File Name Errors::), the
     following error condition is defined for this function:

    `EINVAL'
          The value of PARAMETER is invalid, or the implementation
          doesn't support the PARAMETER for the specific file.

 - Function: long int fpathconf (int FILEDES, int PARAMETER)
     This is just like `pathconf' except that an open file descriptor
     is used to specify the file for which information is requested,
     instead of a file name.

     The following `errno' error conditions are defined for this
     function:

    `EBADF'
          The FILEDES argument is not a valid file descriptor.

    `EINVAL'
          The value of PARAMETER is invalid, or the implementation
          doesn't support the PARAMETER for the specific file.

   Here are the symbolic constants that you can use as the PARAMETER
argument to `pathconf' and `fpathconf'.  The values are all integer
constants.

`_PC_LINK_MAX'
     Inquire about the value of `LINK_MAX'.

`_PC_MAX_CANON'
     Inquire about the value of `MAX_CANON'.

`_PC_MAX_INPUT'
     Inquire about the value of `MAX_INPUT'.

`_PC_NAME_MAX'
     Inquire about the value of `NAME_MAX'.

`_PC_PATH_MAX'
     Inquire about the value of `PATH_MAX'.

`_PC_PIPE_BUF'
     Inquire about the value of `PIPE_BUF'.

`_PC_CHOWN_RESTRICTED'
     Inquire about the value of `_POSIX_CHOWN_RESTRICTED'.

`_PC_NO_TRUNC'
     Inquire about the value of `_POSIX_NO_TRUNC'.

`_PC_VDISABLE'
     Inquire about the value of `_POSIX_VDISABLE'.

`_PC_SYNC_IO'
     Inquire about the value of `_POSIX_SYNC_IO'.

`_PC_ASYNC_IO'
     Inquire about the value of `_POSIX_ASYNC_IO'.

`_PC_PRIO_IO'
     Inquire about the value of `_POSIX_PRIO_IO'.

`_PC_SOCK_MAXBUF'
     Inquire about the value of `_POSIX_PIPE_BUF'.

`_PC_FILESIZEBITS'
     Inquire about the availability of large files on the filesystem.

`_PC_REC_INCR_XFER_SIZE'
     Inquire about the value of `POSIX_REC_INCR_XFER_SIZE'.

`_PC_REC_MAX_XFER_SIZE'
     Inquire about the value of `POSIX_REC_MAX_XFER_SIZE'.

`_PC_REC_MIN_XFER_SIZE'
     Inquire about the value of `POSIX_REC_MIN_XFER_SIZE'.

`_PC_REC_XFER_ALIGN'
     Inquire about the value of `POSIX_REC_XFER_ALIGN'.


File: libc.info,  Node: Utility Limits,  Next: Utility Minimums,  Prev: Pathconf,  Up: System Configuration

Utility Program Capacity Limits
===============================

   The POSIX.2 standard specifies certain system limits that you can
access through `sysconf' that apply to utility behavior rather than the
behavior of the library or the operating system.

   The GNU C library defines macros for these limits, and `sysconf'
returns values for them if you ask; but these values convey no
meaningful information.  They are simply the smallest values that
POSIX.2 permits.

 - Macro: int BC_BASE_MAX
     The largest value of `obase' that the `bc' utility is guaranteed
     to support.

 - Macro: int BC_DIM_MAX
     The largest number of elements in one array that the `bc' utility
     is guaranteed to support.

 - Macro: int BC_SCALE_MAX
     The largest value of `scale' that the `bc' utility is guaranteed
     to support.

 - Macro: int BC_STRING_MAX
     The largest number of characters in one string constant that the
     `bc' utility is guaranteed to support.

 - Macro: int COLL_WEIGHTS_MAX
     The largest number of weights that can necessarily be used in
     defining the collating sequence for a locale.

 - Macro: int EXPR_NEST_MAX
     The maximum number of expressions that can be nested within
     parenthesis by the `expr' utility.

 - Macro: int LINE_MAX
     The largest text line that the text-oriented POSIX.2 utilities can
     support.  (If you are using the GNU versions of these utilities,
     then there is no actual limit except that imposed by the available
     virtual memory, but there is no way that the library can tell you
     this.)

 - Macro: int EQUIV_CLASS_MAX
     The maximum number of weights that can be assigned to an entry of
     the `LC_COLLATE' category `order' keyword in a locale definition.
     The GNU C library does not presently support locale definitions.


File: libc.info,  Node: Utility Minimums,  Next: String Parameters,  Prev: Utility Limits,  Up: System Configuration

Minimum Values for Utility Limits
=================================

`_POSIX2_BC_BASE_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     value of `obase' in the `bc' utility.  Its value is `99'.

`_POSIX2_BC_DIM_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     size of an array in the `bc' utility.  Its value is `2048'.

`_POSIX2_BC_SCALE_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     value of `scale' in the `bc' utility.  Its value is `99'.

`_POSIX2_BC_STRING_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     size of a string constant in the `bc' utility.  Its value is
     `1000'.

`_POSIX2_COLL_WEIGHTS_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     number of weights that can necessarily be used in defining the
     collating sequence for a locale.  Its value is `2'.

`_POSIX2_EXPR_NEST_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     number of expressions nested within parenthesis when using the
     `expr' utility.  Its value is `32'.

`_POSIX2_LINE_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     size of a text line that the text utilities can handle.  Its value
     is `2048'.

`_POSIX2_EQUIV_CLASS_MAX'
     The most restrictive limit permitted by POSIX.2 for the maximum
     number of weights that can be assigned to an entry of the
     `LC_COLLATE' category `order' keyword in a locale definition.  Its
     value is `2'.  The GNU C library does not presently support locale
     definitions.


File: libc.info,  Node: String Parameters,  Prev: Utility Minimums,  Up: System Configuration

String-Valued Parameters
========================

   POSIX.2 defines a way to get string-valued parameters from the
operating system with the function `confstr':

 - Function: size_t confstr (int PARAMETER, char *BUF, size_t LEN)
     This function reads the value of a string-valued system parameter,
     storing the string into LEN bytes of memory space starting at BUF.
     The PARAMETER argument should be one of the `_CS_' symbols listed
     below.

     The normal return value from `confstr' is the length of the string
     value that you asked for.  If you supply a null pointer for BUF,
     then `confstr' does not try to store the string; it just returns
     its length.  A value of `0' indicates an error.

     If the string you asked for is too long for the buffer (that is,
     longer than `LEN - 1'), then `confstr' stores just that much
     (leaving room for the terminating null character).  You can tell
     that this has happened because `confstr' returns a value greater
     than or equal to LEN.

     The following `errno' error conditions are defined for this
     function:

    `EINVAL'
          The value of the PARAMETER is invalid.

   Currently there is just one parameter you can read with `confstr':

`_CS_PATH'
     This parameter's value is the recommended default path for
     searching for executable files.  This is the path that a user has
     by default just after logging in.

`_CS_LFS_CFLAGS'
     The returned string specifies which additional flags must be given
     to the C compiler if a source is compiled using the
     `_LARGEFILE_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS_LDFLAGS'
     The returned string specifies which additional flags must be given
     to the linker if a source is compiled using the
     `_LARGEFILE_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS_LIBS'
     The returned string specifies which additional libraries must be
     linked to the application if a source is compiled using the
     `_LARGEFILE_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS_LINTFLAGS'
     The returned string specifies which additional flags must be given
     to the lint tool if a source is compiled using the
     `_LARGEFILE_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS64_CFLAGS'
     The returned string specifies which additional flags must be given
     to the C compiler if a source is compiled using the
     `_LARGEFILE64_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS64_LDFLAGS'
     The returned string specifies which additional flags must be given
     to the linker if a source is compiled using the
     `_LARGEFILE64_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS64_LIBS'
     The returned string specifies which additional libraries must be
     linked to the application if a source is compiled using the
     `_LARGEFILE64_SOURCE' feature select macro; *note Feature Test
     Macros::.

`_CS_LFS64_LINTFLAGS'
     The returned string specifies which additional flags must be given
     to the lint tool if a source is compiled using the
     `_LARGEFILE64_SOURCE' feature select macro; *note Feature Test
     Macros::.

   The way to use `confstr' without any arbitrary limit on string size
is to call it twice: first call it to get the length, allocate the
buffer accordingly, and then call `confstr' again to fill the buffer,
like this:

     char *
     get_default_path (void)
     {
       size_t len = confstr (_CS_PATH, NULL, 0);
       char *buffer = (char *) xmalloc (len);
     
       if (confstr (_CS_PATH, buf, len + 1) == 0)
         {
           free (buffer);
           return NULL;
         }
     
       return buffer;
     }


File: libc.info,  Node: Cryptographic Functions,  Next: Debugging Support,  Prev: System Configuration,  Up: Top

DES Encryption and Password Handling
************************************

   On many systems, it is unnecessary to have any kind of user
authentication; for instance, a workstation which is not connected to a
network probably does not need any user authentication, because to use
the machine an intruder must have physical access.

   Sometimes, however, it is necessary to be sure that a user is
authorized to use some service a machine provides--for instance, to log
in as a particular user id (*note Users and Groups::).  One traditional
way of doing this is for each user to choose a secret "password"; then,
the system can ask someone claiming to be a user what the user's
password is, and if the person gives the correct password then the
system can grant the appropriate privileges.

   If all the passwords are just stored in a file somewhere, then this
file has to be very carefully protected.  To avoid this, passwords are
run through a "one-way function", a function which makes it difficult to
work out what its input was by looking at its output, before storing in
the file.

   The GNU C library provides a one-way function that is compatible with
the behavior of the `crypt' function introduced in FreeBSD 2.0.  It
supports two one-way algorithms: one based on the MD5 message-digest
algorithm that is compatible with modern BSD systems, and the other
based on the Data Encryption Standard (DES) that is compatible with
Unix systems.

   It also provides support for Secure RPC, and some library functions
that can be used to perform normal DES encryption.

* Menu:

* Legal Problems::              This software can get you locked up, or worse.
* getpass::                     Prompting the user for a password.
* crypt::                       A one-way function for passwords.
* DES Encryption::              Routines for DES encryption.


File: libc.info,  Node: Legal Problems,  Next: getpass,  Up: Cryptographic Functions

Legal Problems
==============

   Because of the continuously changing state of the law, it's not
possible to provide a definitive survey of the laws affecting
cryptography.  Instead, this section warns you of some of the known
trouble spots; this may help you when you try to find out what the laws
of your country are.

   Some countries require that you have a licence to use, possess, or
import cryptography.  These countries are believed to include
Byelorussia, Burma, India, Indonesia, Israel, Kazakhstan, Pakistan,
Russia, and Saudi Arabia.

   Some countries restrict the transmission of encrypted messages by
radio; some telecommunications carriers restrict the transmission of
encrypted messages over their network.

   Many countries have some form of export control for encryption
software.  The Wassenaar Arrangement is a multilateral agreement
between 33 countries (Argentina, Australia, Austria, Belgium, Bulgaria,
Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Ireland, Italy, Japan, Luxembourg, the Netherlands, New
Zealand, Norway, Poland, Portugal, the Republic of Korea, Romania, the
Russian Federation, the Slovak Republic, Spain, Sweden, Switzerland,
Turkey, Ukraine, the United Kingdom and the United States) which
restricts some kinds of encryption exports.  Different countries apply
the arrangement in different ways; some do not allow the exception for
certain kinds of "public domain" software (which would include this
library), some only restrict the export of software in tangible form,
and others impose significant additional restrictions.

   The United States has additional rules.  This software would
generally be exportable under 15 CFR 740.13(e), which permits exports of
"encryption source code" which is "publicly available" and which is
"not subject to an express agreement for the payment of a licensing fee
or royalty for commercial production or sale of any product developed
with the source code" to most countries.

   The rules in this area are continuously changing.  If you know of any
information in this manual that is out-of-date, please report it using
the `glibcbug' script. *Note Reporting Bugs::.


File: libc.info,  Node: getpass,  Next: crypt,  Prev: Legal Problems,  Up: Cryptographic Functions

Reading Passwords
=================

   When reading in a password, it is desirable to avoid displaying it on
the screen, to help keep it secret.  The following function handles this
in a convenient way.

 - Function: char * getpass (const char *PROMPT)
     `getpass' outputs PROMPT, then reads a string in from the terminal
     without echoing it.  It tries to connect to the real terminal,
     `/dev/tty', if possible, to encourage users not to put plaintext
     passwords in files; otherwise, it uses `stdin' and `stderr'.
     `getpass' also disables the INTR, QUIT, and SUSP characters on the
     terminal using the `ISIG' terminal attribute (*note Local Modes::).
     The terminal is flushed before and after `getpass', so that
     characters of a mistyped password are not accidentally visible.

     In other C libraries, `getpass' may only return the first
     `PASS_MAX' bytes of a password.  The GNU C library has no limit, so
     `PASS_MAX' is undefined.

     The prototype for this function is in `unistd.h'.  `PASS_MAX'
     would be defined in `limits.h'.

   This precise set of operations may not suit all possible situations.
In this case, it is recommended that users write their own `getpass'
substitute.  For instance, a very simple substitute is as follows:

     #include <termios.h>
     #include <stdio.h>
     
     ssize_t
     my_getpass (char **lineptr, size_t *n, FILE *stream)
     {
       struct termios old, new;
       int nread;
     
       /* Turn echoing off and fail if we can't. */
       if (tcgetattr (fileno (stream), &old) != 0)
         return -1;
       new = old;
       new.c_lflag &= ~ECHO;
       if (tcsetattr (fileno (stream), TCSAFLUSH, &new) != 0)
         return -1;
     
       /* Read the password. */
       nread = getline (lineptr, n, stream);
     
       /* Restore terminal. */
       (void) tcsetattr (fileno (stream), TCSAFLUSH, &old);
     
       return nread;
     }

   The substitute takes the same parameters as `getline' (*note Line
Input::); the user must print any prompt desired.


File: libc.info,  Node: crypt,  Next: DES Encryption,  Prev: getpass,  Up: Cryptographic Functions

Encrypting Passwords
====================

 - Function: char * crypt (const char *KEY, const char *SALT)
     The `crypt' function takes a password, KEY, as a string, and a
     SALT character array which is described below, and returns a
     printable ASCII string which starts with another salt.  It is
     believed that, given the output of the function, the best way to
     find a KEY that will produce that output is to guess values of KEY
     until the original value of KEY is found.

     The SALT parameter does two things.  Firstly, it selects which
     algorithm is used, the MD5-based one or the DES-based one.
     Secondly, it makes life harder for someone trying to guess
     passwords against a file containing many passwords; without a
     SALT, an intruder can make a guess, run `crypt' on it once, and
     compare the result with all the passwords.  With a SALT, the
     intruder must run `crypt' once for each different salt.

     For the MD5-based algorithm, the SALT should consist of the string
     `$1$', followed by up to 8 characters, terminated by either
     another `$' or the end of the string.  The result of `crypt' will
     be the SALT, followed by a `$' if the salt didn't end with one,
     followed by 22 characters from the alphabet `./0-9A-Za-z', up to
     34 characters total.  Every character in the KEY is significant.

     For the DES-based algorithm, the SALT should consist of two
     characters from the alphabet `./0-9A-Za-z', and the result of
     `crypt' will be those two characters followed by 11 more from the
     same alphabet, 13 in total.  Only the first 8 characters in the
     KEY are significant.

     The MD5-based algorithm has no limit on the useful length of the
     password used, and is slightly more secure.  It is therefore
     preferred over the DES-based algorithm.

     When the user enters their password for the first time, the SALT
     should be set to a new string which is reasonably random.  To
     verify a password against the result of a previous call to
     `crypt', pass the result of the previous call as the SALT.

   The following short program is an example of how to use `crypt' the
first time a password is entered.  Note that the SALT generation is
just barely acceptable; in particular, it is not unique between
machines, and in many applications it would not be acceptable to let an
attacker know what time the user's password was last set.

     #include <stdio.h>
     #include <time.h>
     #include <unistd.h>
     #include <crypt.h>
     
     int
     main(void)
     {
       unsigned long seed[2];
       char salt[] = "$1$........";
       const char *const seedchars =
         "./0123456789ABCDEFGHIJKLMNOPQRST"
         "UVWXYZabcdefghijklmnopqrstuvwxyz";
       char *password;
       int i;
     
       /* Generate a (not very) random seed.
          You should do it better than this... */
       seed[0] = time(NULL);
       seed[1] = getpid() ^ (seed[0] >> 14 & 0x30000);
     
       /* Turn it into printable characters from `seedchars'. */
       for (i = 0; i < 8; i++)
         salt[3+i] = seedchars[(seed[i/5] >> (i%5)*6) & 0x3f];
     
       /* Read in the user's password and encrypt it. */
       password = crypt(getpass("Password:"), salt);
     
       /* Print the results. */
       puts(password);
       return 0;
     }

   The next program shows how to verify a password.  It prompts the user
for a password and prints "Access granted." if the user types `GNU libc
manual'.

     #include <stdio.h>
     #include <string.h>
     #include <unistd.h>
     #include <crypt.h>
     
     int
     main(void)
     {
       /* Hashed form of "GNU libc manual". */
       const char *const pass = "$1$/iSaq7rB$EoUw5jJPPvAPECNaaWzMK/";
     
       char *result;
       int ok;
     
       /* Read in the user's password and encrypt it,
          passing the expected password in as the salt. */
       result = crypt(getpass("Password:"), pass);
     
       /* Test the result. */
       ok = strcmp (result, pass) == 0;
     
       puts(ok ? "Access granted." : "Access denied.");
       return ok ? 0 : 1;
     }

 - Function: char * crypt_r (const char *KEY, const char *SALT, struct
          crypt_data * DATA)
     The `crypt_r' function does the same thing as `crypt', but takes
     an extra parameter which includes space for its result (among
     other things), so it can be reentrant.  `data->initialized' must be
     cleared to zero before the first time `crypt_r' is called.

     The `crypt_r' function is a GNU extension.

   The `crypt' and `crypt_r' functions are prototyped in the header
`crypt.h'.

