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")

}

package main

import "syscall"

func main() {

	// test.dll

	// int add(int x, int y)

	h, err := syscall.LoadLibrary("test.dll")

	if (err != nil){

		panic(err.Error())

	}

	defer syscall.FreeLibrary(h)

	proc, err := syscall.GetProcAddress(h, "add")

	if (err != nil) {

		panic(err.Error())

	}

	r, _, _ := syscall.Syscall(uintptr(proc), 2, 1, 1, 0)

	println("r=", r)

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

	add := dll.NewProc("add")

	ret, _, _ := add.Call(uintptr(1), uintptr(1))

	println("1+1=", ret)

}