golang调用dll

//调用方式

func WindowVersion1() {
	h, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		fmt.Printf("Error: %s\n", err)
		return
	}
	defer syscall.FreeLibrary(h)
	proc, err := syscall.GetProcAddress(h, "GetVersion")
	if err != nil {
		fmt.Printf("Error: %s\n", err)
		return
	}
	r, _, _ := syscall.Syscall(uintptr(proc), 0, 0, 0, 0)
	major := byte(r)
	minor := uint8(r >> 8)
	build := uint16(r >> 16)
	print("windows version ", major, ".", minor, " (Build ", build, ")\n")
}

func WindowVersion2() {
	dll32 := syscall.NewLazyDLL("kernel32.dll")

	g := dll32.NewProc("GetVersion")

	r, _, _ := g.Call()
	major := byte(r)
	minor := uint8(r >> 8)
	build := uint16(r >> 16)
	print("windows version ", major, ".", minor, " (Build ", build, ")\n")
}

//调用c++ dll

使用时将go生成的exe和c++生成的dll放在同一目录下即可.

C++:

//vs 2010,c++嵌入"::MessageBox(NULL, str, _T("..."), MB_OK);"用以调试时会引起程序崩溃.

//dlltest.h
DLL_API int __stdcall test1(LPTSTR s);
DLL_API int __stdcall test2(int *m);

//dlltest.cpp
int __stdcall test1(LPTSTR s)
{
	CStringA sz(s);
	cout<<sz<<endl;
	return 0;
}

int __stdcall test2(int *m)
{
	*m=*m*3+1;
	return 123;
}

go:

func callDll1() {
	dll32 := syscall.NewLazyDLL("dlltest.dll")
	fmt.Println("dll name:", dll32.Name)

	g := dll32.NewProc("_test1@4")
	s := "1k中国fd"

	r1, _, _ := g.Call(uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(s))))
	fmt.Println("callDll1结果:", r1)
}

func callDll2() {
	dll32 := syscall.NewLazyDLL("dlltest.dll")

	g := dll32.NewProc("_test2@4")

	var m int32
	m = 10
	p := &m
	fmt.Printf("%#v\n", p)
	r1, _, _ := g.Call(uintptr(unsafe.Pointer(p)))
	fmt.Println("callDll2结果:", (int32)(r1))
	//获取修改后的m值
	fmt.Println(*(*int32)(unsafe.Pointer(p))) //返回31
}

dll尝试返回*string 报错原因:golang的string是struct以len判断结束,c/c++的string是以'\0'表示结束.,底层数据结果不同导致.所以使用dll传入传出数据时,要小心底层数据类型的一致性问题.