All possible GOOS value?

If I get it right, GOOS is determined when compile the source code.

To better support multiple OS, I'm interested in what GOOS could be.

Of course, there might be infinite possibilities of it, since Go is opensourced. So what I really want is a "common list".

Known values are:

• windows
• linux
• darwin or freebsd or unix? I know that at least one of them must exist.

Note that those values are defined in:

• src/go/build/syslist.go, and
• doc/install/source#environment.

With Go 1.5 (Q3 2015), GOARCH will become much more complete.
See commit 1eebb91 by Minux Ma (minux)

> ## go/build: reserve GOARCH values for all common architectures
>
> Whenever we introduce a new GOARCH, older Go releases won't recognize them and this causes trouble for both our users and us (we need to add unnecessary build tags).
>
> Go 1.5 has introduced three new GOARCHes so far: arm64 ppc64 ppc64le, we can take the time to introduce GOARCHes for all common architectures that Go might support in the future to avoid the problem.

const goosList = "android darwin dragonfly freebsd linux nacl \ 
  netbsd openbsd plan9 solaris windows "

const goarchList = "386 amd64 amd64p32 arm arm64 ppc64 ppc64le \
   mips mipsle mips64 mips64le mips64p32 mips64p32le \ # (new)
   ppc s390 s390x sparc sparc64 " # (new)

The list is still being review in Change 9644, with comments like:

> I wouldn't bother with Itanium. It's basically a dead architecture.
Plus, it's so hard to write a compiler for it that I really can't see it happening except as a labor of love, and nobody loves the Itanium.

The official documentation now (GO 1.5+ Q3 2015) reflects that completed list.

Update 2018: as documented in Giorgos Oikonomou's answer, Go 1.7 (Q1 2016) has introduced the
go tool dist list command.
See commit c3ecded: it fixes issue 12270 opened in Q3 2015:

> To easier write tooling for cross compiling it would be good to programmatically get the possible combinations of GOOS and GOARCH.

This was implemented in CL 19837

> cmd/dist: introduce list subcommand to list all supported platforms

You can list in plain text, or in json:

> go tool dist list -json
[
        {
                "GOOS": "android",
                "GOARCH": "386",
                "CgoSupported": true
        },
        ...
]

As Mark Bates tweeted:

> Bonus: Column output properly formatted for display:
>
> go tool dist list | column -c 75 | column -t

I think you're looking for this list of possible GOOS and GOARCH combinations, in this section:

http://golang.org/doc/install/source#environment

> $GOOS and $GOARCH
> The name of the target operating system and
> compilation architecture. These default to the values of $GOHOSTOS and
> $GOHOSTARCH respectively (described below).
>
> Choices for $GOOS are darwin (Mac OS X 10.8 and above and iOS),
> dragonfly, freebsd, linux, netbsd, openbsd, plan9, solaris and
> windows. Choices for $GOARCH are amd64 (64-bit x86, the most mature
> port), 386 (32-bit x86), arm (32-bit ARM), arm64 (64-bit ARM), ppc64le
> (PowerPC 64-bit, little-endian), ppc64 (PowerPC 64-bit, big-endian),
> mips64le (MIPS 64-bit, little-endian), and mips64 (MIPS 64-bit,
> big-endian). mipsle (MIPS 32-bit, little-endian), and mips (MIPS
> 32-bit, big-endian).
>
> The valid combinations of $GOOS and $GOARCH are:
>
> $GOOS $GOARCH
> android arm
> darwin 386
> darwin amd64
> darwin arm
> darwin arm64
> dragonfly amd64
> freebsd 386
> freebsd amd64
> freebsd arm
> linux 386
> linux amd64
> linux arm
> linux arm64
> linux ppc64
> linux ppc64le
> linux mips
> linux mipsle
> linux mips64
> linux mips64le
> netbsd 386
> netbsd amd64
> netbsd arm
> openbsd 386
> openbsd amd64
> openbsd arm
> plan9 386
> plan9 amd64
> solaris amd64
> windows 386
> windows amd64

You can see the list of supported platform by running:

go tool dist list

and this will print(depending on the Go version):

android/386
android/amd64
android/arm
android/arm64
darwin/386
darwin/amd64
darwin/arm
darwin/arm64
dragonfly/amd64
freebsd/386
freebsd/amd64
freebsd/arm
linux/386
linux/amd64
linux/arm
linux/arm64
linux/mips
linux/mips64
linux/mips64le
linux/mipsle
linux/ppc64
linux/ppc64le
linux/s390x
nacl/386
nacl/amd64p32
nacl/arm
netbsd/386
netbsd/amd64
netbsd/arm
openbsd/386
openbsd/amd64
openbsd/arm
plan9/386
plan9/amd64
plan9/arm
solaris/amd64
windows/386
windows/amd64

And the official documentation for the tool:

https://godoc.org/github.com/golang/go/src/cmd/dist

To cross compile use:

GOOS=darwin GOARCH=386 go build main.go