Golang调用windows下的dll动态库中的函数

package main

import (

	"fmt"

	"syscall"

	"time"

	"unsafe"

)

const (

	MB_OK                = 0x00000000

	MB_OKCANCEL          = 0x00000001

	MB_ABORTRETRYIGNORE  = 0x00000002

	MB_YESNOCANCEL       = 0x00000003

	MB_YESNO             = 0x00000004

	MB_RETRYCANCEL       = 0x00000005

	MB_CANCELTRYCONTINUE = 0x00000006

	MB_ICONHAND          = 0x00000010

	MB_ICONQUESTION      = 0x00000020

	MB_ICONEXCLAMATION   = 0x00000030

	MB_ICONASTERISK      = 0x00000040

	MB_USERICON          = 0x00000080

	MB_ICONWARNING       = MB_ICONEXCLAMATION

	MB_ICONERROR         = MB_ICONHAND

	MB_ICONINFORMATION   = MB_ICONASTERISK

	MB_ICONSTOP          = MB_ICONHAND

	MB_DEFBUTTON1 = 0x00000000

	MB_DEFBUTTON2 = 0x00000100

	MB_DEFBUTTON3 = 0x00000200

	MB_DEFBUTTON4 = 0x00000300

)

func abort(funcname string, err syscall.Errno) {

	panic(funcname + " failed: " + err.Error())

}

var (

	//    kernel32, _        = syscall.LoadLibrary("kernel32.dll")

	//    getModuleHandle, _ = syscall.GetProcAddress(kernel32, "GetModuleHandleW")

	user32, _     = syscall.LoadLibrary("user32.dll")

	messageBox, _ = syscall.GetProcAddress(user32, "MessageBoxW")

)

func IntPtr(n int) uintptr {

	return uintptr(n)

}

func StrPtr(s string) uintptr {

	return uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(s)))

}

func MessageBox(caption, text string, style uintptr) (result int) {

	ret, _, callErr := syscall.Syscall9(messageBox,

		4,

		0,

		StrPtr(text),

		StrPtr(caption),

		style,

		0, 0, 0, 0, 0)

	if callErr != 0 {

		abort("Call MessageBox", callErr)

	}

	result = int(ret)

	return

}

//func GetModuleHandle() (handle uintptr) {

//    if ret, _, callErr := syscall.Syscall(getModuleHandle, 0, 0, 0, 0); callErr != 0 {

//        abort("Call GetModuleHandle", callErr)

//    } else {

//        handle = ret

//    }

//    return

//}

// windows下的第二种DLL方法调用

func ShowMessage2(title, text string) {

	user32 := syscall.NewLazyDLL("user32.dll")

	MessageBoxW := user32.NewProc("MessageBoxW")

	MessageBoxW.Call(IntPtr(0), StrPtr(text), StrPtr(title), IntPtr(0))

}

func main() {

	//    defer syscall.FreeLibrary(kernel32)

	defer syscall.FreeLibrary(user32)

	//fmt.Printf("Retern: %d\n", MessageBox("Done Title", "This test is Done.", MB_YESNOCANCEL))

	num := MessageBox("Done Title", "This test is Done.", MB_YESNOCANCEL)

	fmt.Printf("Get Retrun Value Before MessageBox Invoked: %d\n", num)

	ShowMessage2("windows下的第二种DLL方法调用", "HELLO !")

	time.Sleep(3 * time.Second)

}

func init() {

	fmt.Print("Starting Up\n")

}