Go

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Reason: Mention delve. Perhaps in a Tools section. Also should explain tinygo. (Discuss in Talk:Go)

Go is a statically-typed language with syntax loosely derived from that of C, adding garbage collected memory management, type safety, some dynamic-typing capabilities, additional built-in types such as variable-length arrays and key-value maps, and a large standard library.

Installation

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Reason: Recommends go over gcc-go without stating why. (Discuss in Talk:Go#gccgo vs gc)

The standard Go compiler is go, which can be installed from the go package. The go command also include various tooling such as go get, go doc, etc. An alternative is gcc-go, which is a Go frontend for the GNU Compiler Collection (GCC). In some cases gccgo may do better optimisations. When in doubt: use go.

An additional package that most Go developers will want to install is go-tools. This will provide various commonly used tools which will make working with Go easier, such as goimports, guru, gorename, etc.

Test your installation

You can check that Go is installed correctly by building a simple program, as follows:

hello.go

package main

import "fmt"

func main() {
    fmt.Println("Hello, Arch!")
}

Then run it with the go tool:

$ go run hello.go

Hello, Arch!

Compilation with standard gc compiler (same as go build -compiler=gc hello.go):

$ go build hello.go

Compilation with gccgo (same as go build -compiler=gccgo hello.go):

$ gccgo hello.go -o hello

$GOPATH

Go expects the source code to live inside $GOPATH, which is set to ~/go by default.

Tip: You can see all Go variables by running go env

Create that workspace:

$ mkdir -p ~/go/src

The ~/go/src directory is used to store the sources of the packages. When compiling Go will also create bin for executables and pkg to cache individual packages. You will probably want to add ~/go/bin to the $PATH environment variable to run installed Go:

export PATH="$PATH:$HOME/go/bin"

Run go help gopath for more information.

Tip: $GOPATH works like $PATH and can contain multiple entries, this can be useful to split out packages downloaded with go get and your own source code; e.g. GOPATH=$HOME/go:$HOME/mygo

Cross compiling to other platforms

The go command can natively cross-compile to a number of platforms.

If cgo is not required for your build, then simply specify the target OS and architecture as env vars to go build:

$ GOOS=linux GOARCH=arm64 go build .

See the official documentation for the valid combinations of $GOOS and $GOARCH.

On the other hand, if cgo is required for your build, you have to provide the path to your C/C++ cross-compilers, via the $CC/$CXX env vars.

Say you want to cross-compile for $GOOS=linux and $GOARCH=arm64.

You need first to install the aarch64-linux-gnu-gcc cross-compiler.

Here is a sample program that requires cgo, so that we can test the cross-compilation process:

$ cat > hello.go <<EOF
package main

// #include <stdio.h>
// void hello() {  puts("Hello, Arch!"); }
import "C"

func main() { C.hello() }
EOF

Then, you can cross-compile it like this:

$ GOOS=linux GOARCH=arm64 CGO_ENABLED=1 CC=/usr/bin/aarch64-linux-gnu-gcc go build hello.go

You can check that the architecture of the generated binary is actually aarch64:

$ file hello
hello: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, BuildID[sha1]=b1d92ae8840a019f36cc2aee4606b6ae4a581bf1, for GNU/Linux 3.7.0, not stripped

If you copy hello to a suitable host, you can test-run it:

[alarm@rpi3 ~]$ uname -a
Linux alarm 5.3.8-1-ARCH #1 SMP Tue Oct 29 19:31:23 MDT 2019 aarch64 GNU/Linux
[alarm@arpi3 ~]$ ./hello
Hello, Arch!

Troubleshooting

Jetbrains Go Plugin

If you are using a Jetbrains IDE and the Go plugin cannot find your Go SDK path, you might be using an incompatible package. Remove the gcc-go package and replace it with go. If your $GOPATH is set, the IDE should now be able to find your Go SDK at /usr/lib/go.

Go

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