## Release History

This page summarizes the changes between tagged releases of Go. For full details, see the Mercurial change log.

### 2010-01-13

    build: $GOBIN should no longer be required in $PATH (thanks Devon H. O'Dell),
    	new package target "make bench" to run benchmarks
    8g: faster float -> uint64 conversion (thanks Evan Shaw)
    5g, 6g, 8g:
    	clean opnames.h to avoid stale errors (thanks Yongjian Xu),
    	a handful of small compiler fixes
    5g, 6g, 8g, 5l, 6l, 8l: ignore $GOARCH, which is implied by name of tool
    6prof: support for writing input files for google-perftools's pprof
    asn1: fix a few structure-handling bugs
    cgo: many bug fixes (thanks Devon H. O'Dell)
    codereview: repeated "hg mail" sends "please take another look"
    gob: reserve ids for future expansion
    godoc: distinguish HTML generation from plain text HTML escaping (thanks Roger Peppe)
    gofmt: minor bug fixes, removed -oldprinter flag
    http: add CanonicalPath (thanks Ivan Krasin),
    	avoid header duplication in Response.Write,
    	correctly escape/unescape URL sections
    io: new interface ReadByter
    json: better error, pointer handling in Marshal (thanks Ivan Krasin)
    libmach: disassembly of FUCOMI, etc (thanks Evan Shaw)
    math: special cases for most functions and 386 hardware Sqrt (thanks Charles Dorian)
    misc/dashboard: beginning of a build dashboard at godashboard.appspot.com.
    misc/emacs: handling of new semicolon rules (thanks Austin Clements),
    	empty buffer bug fix (thanks Kevin Ballard)
    misc/kate: highlighting improvements (tahnks Evan Shaw)
    os/signal: add signal names: signal.SIGHUP, etc (thanks David Symonds)
    runtime: preliminary Windows support (thanks Hector Chu),
    	preemption polling to reduce garbage collector pauses
    scanner: new lightweight scanner package
    template: bug fix involving spaces before a delimited block
    test/bench: updated timings
    time: new Format, Parse functions

### 2010-01-05

    This release is mainly bug fixes.  There are no language changes.

    6prof: now works on 386
    8a, 8l: add FCOMI, FCOMIP, FUCOMI, and FUCOMIP (thanks Evan Shaw)
    big: fix ProbablyPrime on small numbers
    container/vector: faster []-based implementation (thanks Jan Mercl)
    crypto/tls: extensions and Next Protocol Negotiation
    gob: one encoding bug fix, one decoding bug fix
    image/jpeg: support for RST markers
    image/png: support for transparent paletted images
    misc/xcode: improved support (thanks Ken Friedenbach)
    net: return nil Conn on error from Dial (thanks Roger Peppe)
    regexp: add Regexp.NumSubexp (thanks Peter Froehlich)
    syscall: add Nanosleep on FreeBSD (thanks Devon H. O'Dell)
    template: can use map in .repeated section

    There is now a public road map, in the repository and online
    at http://golang.org/doc/devel/roadmap.html.

### 2009-12-22

    Since the last release there has been one large syntactic change to
    the language, already discussed extensively on this list: semicolons
    are now implied between statement-ending tokens and newline characters.
    See http://groups.google.com/group/golang-nuts/t/5ee32b588d10f2e9 for
    details.

    By default, gofmt now parses and prints the new lighter weight syntax.
    To convert programs written in the old syntax, you can use:

    	gofmt -oldparser -w *.go

    Since everything was being reformatted anyway, we took the opportunity to
    change the way gofmt does alignment.  Now gofmt uses tabs at the start
    of a line for basic code alignment, but it uses spaces for alignment of
    interior columns.  Thus, in an editor with a fixed-width font, you can
    choose your own tab size to change the indentation, and no matter what
    tab size you choose, columns will be aligned properly.

    In addition to the syntax and formatting changes, there have been many
    smaller fixes and updates:

    6g,8g,5g: many bug fixes, better registerization,
       build process fix involving mkbuiltin (thanks Yongjian Xu),
       method expressions for concrete types
    8l: support for Windows PE files (thanks Hector Chu)
    bytes: more efficient Buffer handling
    bytes, strings: new function Fields (thanks Andrey Mirtchovski)
    cgo: handling of enums (thanks Moriyoshi Koizumi),
        handling of structs with bit fields, multiple files (thanks Devon H. O'Dell),
        installation of .so to non-standard locations
    crypto/sha256: new package for SHA 256 (thanks Andy Davis)
    encoding/binary: support for slices of fixed-size values (thanks Maxim Ushakov)
    exp/vector: experimental alternate vector representation (thanks Jan Mercl)
    fmt: %p for chan, map, slice types
    gob: a couple more bug fixes
    http: support for basic authentication (thanks Ivan Krasin)
    image/jpeg: basic JPEG decoder
    math: correct handling of Inf and NaN in Pow (thanks Charles Dorian)
    misc/bash: completion file for bash (thanks Alex Ray)
    os/signal: support for handling Unix signals (thanks David Symonds)
    rand: Zipf-distributed random values (thanks William Josephson)
    syscall: correct error return bug on 32-bit machines (thanks Christopher Wedgwood)
    syslog: new package for writing to Unix syslog daemon (thanks Yves Junqueira)
    template: will automatically invoke niladic methods
    time: new ISO8601 format generator (thanks Ben Olive)
    xgb: converted generator to new syntax (thanks Tor Andersson)
    xml: better mapping of tag names to Go identifiers (thanks Kei Son),
        better handling of unexpected EOF (thanks Arvindh Rajesh Tamilmani)

### 2009-12-09

    Since the last release there are two changes to the language:

    * new builtin copy(dst, src) copies n = min(len(dst), len(src))
      elements to dst from src and returns n.  It works correctly
      even if dst and src overlap.  bytes.Copy is gone.
      Convert your programs using:
          gofmt -w -r 'bytes.Copy(d, s) -> copy(d, s)' *.go

    * new syntax x[lo:] is shorthand for x[lo:len(x)].
      Convert your programs using:
          gofmt -w -r 'a[b:len(a)] -> a[b:]' *.go

    In addition, there have been many smaller fixes and updates:

    * 6g/8g/5g: many bug fixes
    * 8g: fix 386 floating point stack bug (thanks Charles Dorian)
    * all.bash: now works even when $GOROOT has spaces (thanks Sergio Luis O. B. Correia),
        starting to make build work with mingw (thanks Hector Chu),
        FreeBSD support (thanks Devon O'Dell)
    * big: much faster on 386.
    * bytes: new function IndexByte, implemented in assembly
        new function Runes (thanks Peter Froehlich),
        performance tuning in bytes.Buffer.
    * codereview: various bugs fixed
    * container/vector: New is gone; just declare a Vector instead.
        call Resize to set len and cap.
    * cgo: many bug fixes (thanks Eden Li)
    * crypto: added MD4 (thanks Chris Lennert),
        added XTEA (thanks Adrian O'Grady).
    * crypto/tls: basic client
    * exp/iterable: new functions (thanks Michael Elkins)
    * exp/nacl: native client tree builds again
    * fmt: preliminary performance tuning
    * go/ast: more powerful Visitor (thanks Roger Peppe)
    * gob: a few bug fixes
    * gofmt: better handling of standard input, error reporting (thanks Fazlul Shahriar)
        new -r flag for rewriting programs
    * gotest: support for Benchmark functions (thanks Trevor Strohman)
    * io: ReadFile, WriteFile, ReadDir now in separate package io/ioutil.
    * json: new Marshal function (thanks Michael Hoisie),
        better white space handling (thanks Andrew Skiba),
        decoding into native data structures (thanks Sergey Gromov),
        handling of nil interface values (thanks Ross Light).
    * math: correct handling of sin/cos of large angles
    * net: better handling of Close (thanks Devon O'Dell and Christopher Wedgwood)
        support for UDP broadcast (thanks Jonathan Wills),
        support for empty packets
    * rand: top-level functions now safe to call from multiple goroutines
    (thanks Roger Peppe).
    * regexp: a few easy optimizations
    * rpc: better error handling, a few bug fixes
    * runtime: better signal handling on OS X, malloc fixes,
        global channel lock is gone.
    * sync: RWMutex now allows concurrent readers (thanks Péter Szabó)
    * template: can use maps as data (thanks James Meneghello)
    * unicode: updated to Unicode 5.2.
    * websocket: new package (thanks Fumitoshi Ukai)
    * xgb: preliminary X Go Bindings (thanks Tor Andersson)
    * xml: fixed crash (thanks Vish Subramanian)
    * misc: bbedit config (thanks Anthony Starks),
        kate config (thanks Evan Shaw)