第一个Go程序

go env -w GO111MODULE=auto

$ go env GOPATH // 通过go env 可以查看go语言设置相关的所有变量
E:\Golang       // 这是我的工作目录

mkdir bin pkg src

package main

import "fmt"

func main() {
        fmt.Println("hello world, this is my first golang program!")
}

$ go run src/day1/hello.go 
hello world, this is my first golang program!

go build -o day1/hello.exe day1/hello.go   // 编译hello.go, 输出二进制目标文件hello.exe
./day1/hello.exe     // 运行编译好的hello.exe
hello world, this is my first golang program!

$ go env
set GO111MODULE=auto
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\yumaojun\AppData\Local\go-build    
set GOENV=C:\Users\yumaojun\AppData\Roaming\go\env      
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=E:\Golang\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=E:\Golang
set GOPRIVATE=
set GOPROXY=https://goproxy.cn
set GOROOT=C:\Program Files\Go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.16.4
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\yumaojun\AppData\Local\Temp\go-build483455790=/tmp/go-build -gno-record-gcc-switches

go env GO111MODULE

go env -w GO111MODULE=auto

$ go tool
addr2line
api
asm
buildid
cgo
compile   // 编译源代码, 生成静态库或者目标文件
cover
dist
doc
fix
go_bootstrap
link     // 链接目标文件和目标文件依赖的静态库 生成最终的可执行二进制文件
nm
objdump
pack
pprof
test2json
trace   
vet

mkdir day1/compile

package pkg

import "fmt"

func Demo() {
        fmt.Println("This is demo for go install")
}

package main

import "day1/compile/pkg"

func main() {
        pkg.Demo()
}

go env -w GO111MODULE=auto // 为了让go install 命令能正常生成静态库到pkg目录下, 我们首先需要关闭go mod
go install day1/compile/pkg  // 使用go install 安装依赖包, 安装过后静态库会放置到 GOPATH下的pkg/<platform>下

cd /day1/compile  // 切换到compile目录下 进行编译与链接
go tool compile -I /e/Golang/pkg/windows_amd64 main.go // 编译原文件, 指定静态库搜索目录

go tool link -o main.exe -L /e/Golang/pkg/windows_amd64/  main.o // 将目标文件和静态库链接成一个二进制可执行文件

./main.exe

go get -v golang.org/x/tools/gopls 

ls /e/Golang/pkg/windows_amd64/demo

go clean -i -n