Golang通过syscall调用windows dll方法

本用例在GO 1.4.2 上编译执行通过,直接上CODE:

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下的另一种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下的另一种DLL方法调用", "HELLO !")
  time.Sleep(3 * time.Second)
}
func init() {
  fmt.Print("Starting Up\n")
}

运行效果:

---

syscall延伸阅读:

golang的OLE调用工具包

https://github.com/mattn/go-ole

---

以下介绍来源:http://wendal.net/2013/0406.html

syscall.Syscall系列方法

当前共5个方法

syscall.Syscallsyscall.Syscall6syscall.Syscall9syscall.Syscall12syscall.Syscall15

分别对应 3个/6个/9个/12个/15个参数或以下的调用

参数都形如

syscall.Syscall(trap, nargs, a1, a2, a3)

第二个参数, nargs 即参数的个数,一旦传错, 轻则调用失败,重者直接APPCARSH

多余的参数, 用0代替

调用示例

获取磁盘空间

//首先,准备输入参数, GetDiskFreeSpaceEx需要4个参数, 可查MSDNdir := "C:"lpFreeBytesAvailable := int64(0) 
//注意类型需要跟API的类型相符lpTotalNumberOfBytes := int64(0)lpTotalNumberOfFreeBytes := int64(0)
//获取方法的引用kernel32, err := syscall.LoadLibrary("Kernel32.dll") 
// 严格来说需要加上 defer syscall.FreeLibrary(kernel32)
// GetDiskFreeSpaceEx, err := syscall.GetProcAddress(syscall.Handle(kernel32), "GetDiskFreeSpaceExW")
//执行之. 因为有4个参数,故取Syscall6才能放得下. 最后2个参数,自然就是0了r, _, errno := syscall.Syscall6(uintptr(GetDiskFreeSpaceEx), 4,
      uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr("C:"))),
      uintptr(unsafe.Pointer(&lpFreeBytesAvailable)),
      uintptr(unsafe.Pointer(&lpTotalNumberOfBytes)),
      uintptr(unsafe.Pointer(&lpTotalNumberOfFreeBytes)), 0, 0)
      // 注意, errno并非error接口的, 不可能是nil// 而且,根据MSDN的说明,返回值为0就fail, 不为0就是成功if r != 0 {
  log.Printf("Free %dmb", lpTotalNumberOfFreeBytes/1024/1024)}

简单点的方式? 用syscall.Call

跟Syscall系列一样, Call方法最多15个参数. 这里用来Must开头的方法, 如不存在,会panic.

  h := syscall.MustLoadDLL("kernel32.dll")
  c := h.MustFindProc("GetDiskFreeSpaceExW")
  lpFreeBytesAvailable := int64(0)
  lpTotalNumberOfBytes := int64(0)
  lpTotalNumberOfFreeBytes := int64(0)
  r2, _, err := c.Call(uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr("F:"))),
    uintptr(unsafe.Pointer(&lpFreeBytesAvailable)),
    uintptr(unsafe.Pointer(&lpTotalNumberOfBytes)),
    uintptr(unsafe.Pointer(&lpTotalNumberOfFreeBytes)))
  if r2 != 0 {
    log.Println(r2, err, lpFreeBytesAvailable/1024/1024)
  

本文来自:开源中国博客

感谢作者:hotkit

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