知识点
跨平台编译
本文目标
在 连载九 讲解构建 Scratch 镜像时，我们编译可执行文件用了另外一个形式的命令，如下：
$ CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o go-gin-example .
我想你可能会有疑问，今天本文会针对这块进行讲解。
说明
我们将讲解命令各个参数的作用，希望你在阅读时，将每一项串联起来，你会发现这就是交叉编译相关的小知识
Golang一、CGO_ENABLED
作用：
cgo意义：
cgo小结：
Scratchdockercgocgocgocgo补充：
golangcgogo env$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
...
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
...
二、GOOS
用于标识（声明）程序构建环境的目标操作系统
如：
linux
windows
三、GOARCH
用于标识（声明）程序构建环境的目标计算架构
若不设置，默认值与程序运行环境的目标计算架构一致（案例就是采用的默认值）
如：
amd64
386
| 系统 | GOOS | GOARCH |
|---|---|---|
| Windows 32 位 | windows | 386 |
| Windows 64 位 | windows | amd64 |
| OS X 32 位 | darwin | 386 |
| OS X 64 位 | darwin | amd64 |
| Linux 32 位 | linux | 386 |
| Linux 64 位 | linux | amd64 |
四、GOHOSTOS
用于标识（声明）程序运行环境的目标操作系统
五、GOHOSTARCH
用于标识（声明）程序运行环境的目标计算架构
六、go build
-a
强制重新编译，简单来说，就是不利用缓存或已编译好的部分文件，直接所有包都是最新的代码重新编译和关联
-installsuffix
作用：
在软件包安装的目录中增加后缀标识，以保持输出与默认版本分开
补充：
-race-racerace-o
指定编译后的可执行文件名称
小结
大部分参数指令，都有一定关联性，且与交叉编译的知识点相关，可以好好品味一下
go build help$ go help build
usage: go build [-o output] [-i] [build flags] [packages]
...
-a
force rebuilding of packages that are already up-to-date.
-n
print the commands but do not run them.
-p n
the number of programs, such as build commands or
test binaries, that can be run in parallel.
The default is the number of CPUs available.
-race
enable data race detection.
Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.
-msan
enable interoperation with memory sanitizer.
Supported only on linux/amd64,
and only with Clang/LLVM as the host C compiler.
-v
print the names of packages as they are compiled.
-work
print the name of the temporary work directory and
do not delete it when exiting.
-x
print the commands.
-asmflags '[pattern=]arg list'
arguments to pass on each go tool asm invocation.
-buildmode mode
build mode to use. See 'go help buildmode' for more.
-compiler name
name of compiler to use, as in runtime.Compiler (gccgo or gc).
-gccgoflags '[pattern=]arg list'
arguments to pass on each gccgo compiler/linker invocation.
-gcflags '[pattern=]arg list'
arguments to pass on each go tool compile invocation.
-installsuffix suffix
a suffix to use in the name of the package installation directory,
in order to keep output separate from default builds.
If using the -race flag, the install suffix is automatically set to race
or, if set explicitly, has _race appended to it. Likewise for the -msan
flag. Using a -buildmode option that requires non-default compile flags
has a similar effect.
-ldflags '[pattern=]arg list'
arguments to pass on each go tool link invocation.
-linkshared
link against shared libraries previously created with
-buildmode=shared.
-pkgdir dir
install and load all packages from dir instead of the usual locations.
For example, when building with a non-standard configuration,
use -pkgdir to keep generated packages in a separate location.
-tags 'tag list'
a space-separated list of build tags to consider satisfied during the
build. For more information about build tags, see the description of
build constraints in the documentation for the go/build package.
-toolexec 'cmd args'
a program to use to invoke toolchain programs like vet and asm.
For example, instead of running asm, the go command will run
'cmd args /path/to/asm <arguments for asm>'.
...
参考
本系列示例代码
go-gin-example
书籍
Go 并发编程实战 第二版