Three new books, Go Optimizations 101, Go Details & Tips 101 and Go Generics 101 are published now. It is most cost-effective to buy all of them through this book bundle in the Leanpub book store.

More Go Related Topics

Go 101 articles mainly focus on syntax and semantics in Go. There are some other Go related topics which are not covered in Go 101. The remaining of the current article will make simple introductions to those topics and provide some web links for readers to dig more into them.

Profiling, Benchmarks and Unit/Fuzzing Tests

We can use go test command in Go Toolchain to run tests and benchmarks. Test source file names must end with _test.go. Go Toolchain also supports profiling Go programs. Please read the following articles for more details.


gccgo is another Go compiler maintained by the Go core team. It is mainly used to verify the correctness of the standard Go compiler (gc). We can use the -compiler=gccgo build option in several Go Toolchain commands to use the gccgo compiler instead of the gc compiler. For example, go run -compiler=gccgo main.go. This option requires the gccgo program is installed. Once the gccgo program is installed, we can also use the gccgo command directly to compile Go code.

The go/* Standard Packages

The go/* standard packages provide functionalities of parsing Go source files, which are very useful to write custom Go tools. Please read go/types: The Go Type Checker and package documentation for how to use these packages.

System Calls

We can make system calls by call the functions exported by the syscall standard package. Please beware that, different from other standard packages, the functions in the syscall standard package are operating system dependent.

Go Assembly

Go functions can be implemented with Go assembly language. Go assembly language is a cross-architectures (though not 100%) assembly language. Go assembly language is often used to implement some functions which are critical for Go program execution performances.

For more details, please follow the following links.


We can call C code from Go code, and vice versa, through the cgo mechanism. Please follow the following links for details.

It is possible to use C++ libraries through cgo by wrapping C++ libraries as C functions.

Please note that using cgo in code may make it is hard to maintain cross-platform compatibility of Go programs, and the calls between Go and C code are some less efficient than Go-Go and C-C calls.

Cross-Platform Compiling

The standard Go compiler supports cross-platform compiling. By setting the GOOS and GOARCH environments before running the go build command, we can build a Windows executable on a Linux machine, and vice versa. Please read the following articles for details. In particular, since Go 1.11, Go Toolchain starts to support WebAssembly as a new kind of GOARCH. Please read this wiki article for details.

Compiler Directives

The standard Go compiler supports several compiler directives. A directive appears as a comment line like //go:DirectiveName args. For examples, we can use the go:generate directive to generate code and use the go:embed directive (introduced in Go 1.16) to embed some data files in code.

Build Constraints (Tags)

We can use build constraints to let compilers build source files selectively (a.k.a., ignore some source files). A build constraint is also called a build tag. A build constraint can appear as a comment line like // +build constraints or appear as the suffix in the base name of a source file. Please note: the new //go:build directive introduced in Go 1.17 will retire the old // +build constraints lines eventually.

More Build Modes

The go build command in Go Toolchain supports several build modes. Please run go help buildmode to show the available build modes or read the explanations for -buildmode option instead. Except the default build mode, the most used build mode may be the plugin build mode. We can use the functions in the plugin standard package to load and use the Go plugin files outputted by using the plugin build mode.


The Go 101 project is hosted on Github. Welcome to improve Go 101 articles by submitting corrections for all kinds of mistakes, such as typos, grammar errors, wording inaccuracies, description flaws, code bugs and broken links.

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Tapir, the author of Go 101, has been on writing the Go 101 series books and maintaining the website since 2016 July. New contents will be continually added to the book and the website from time to time. Tapir is also an indie game developer. You can also support Go 101 by playing Tapir's games (made for both Android and iPhone/iPad):
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