golang 编译 dll 过程中需要用到 gcc,所以先安装 MinGW。
windows 64 位系统应下载 MinGW 的 64 位版本: https://sourceforge.net/projects/mingw-w64/
下载后运行 mingw-w64-install.exe,完成 MingGW 的安装。
首先撰写 golang 程序 exportgo.go:
package main
import "C"
import "fmt"
//export PrintBye
func PrintBye() {
fmt.Println("From DLL: Bye!")
}
//export Sum
func Sum(a int, b int) int {
return a + b;
}
func main() {
// Need a main function to make CGO compile package as C shared library
}
编译成 DLL 文件:
go build -buildmode=c-shared -o exportgo.dll exportgo.go
编译后得到 exportgo.dll 和 exportgo.h 两个文件。
参考 exportgo.h 文件中的函数定义,撰写 C# 文件 importgo.cs:
using System;
using System.Runtime.InteropServices;
namespace HelloWorld
{
class Hello
{
[DllImport("exportgo.dll", EntryPoint="PrintBye")]
static extern void PrintBye();
[DllImport("exportgo.dll", EntryPoint="Sum")]
static extern int Sum(int a, int b);
static void Main()
{
Console.WriteLine("Hello World!");
PrintBye();
Console.WriteLine(Sum(33, 22));
}
编译 CS 文件得到 exe
csc importgo.cs
将 exe 和 dll 放在同一目录下,运行。
>importgo.exe
Hello World!
From DLL: Bye!
55
golang 中的 string 参数在 C# 中可以如下引用:
public struct GoString
{
public string Value { get; set; }
public int Length { get; set; }
public static implicit operator GoString(string s)
{
return new GoString() { Value = s, Length = s.Length };
}
public static implicit operator string(GoString s) => s.Value;
}
// func.go
package main
import "C"
import "fmt"
//export Add
func Add(a C.int, b C.int) C.int {
return a + b
}
//export Print
func Print(s *C.char) {
/*
函数参数可以用 string, 但是用*C.char更通用一些。
由于string的数据结构,是可以被其它go程序调用的,
但其它语言(如 python)就不行了
*/
print("Hello ", C.GoString(s)) //这里不能用fmt包,会报错,调了很久...
}
func main() {
}
编译
go build -ldflags "-s -w" -buildmode=c-shared -o func.dll func.go
还是有点大的,880KB,纯C 编译的只有48KB,应该是没有包含全部的依赖吧,go是全包进来了
Go 调用
package main
import (
"fmt"
"syscall"
)
func main() {
dll := syscall.NewLazyDLL("func.dll")
add := dll.NewProc("Add")
prt := dll.NewProc("Print")
r, err, msg := add.Call(32, 44)
fmt.Println(r)
fmt.Println(err)
fmt.Println(msg)
name := C.CString("Andy")
prt.Call(uintptr(unsafe.Pointer(name)))
}
out:
76
0
The operation completed successfully.
Hello Andy
Python 调用
from ctypes import CDLL, c_char_p
dll = CDLL("func.dll")
dll.Add(32, 33)
dll.Print(c_char_p(bytes("Andy", "utf8")))
C++调用
#include
#include
using namespace std;
typedef int(*pAdd)(int a, int b);
typedef void(*pPrt)(char* s);
int main(int argc, char *argv[])
{
HMODULE dll= LoadLibraryA("func.dll");
pAdd add = (pAdd)GetProcAddress(dll, "Add");
pPrt prt = (pPrt)GetProcAddress(dll, "Print");
cout << add(321, 33) << endl;
prt("Andy");
FreeLibrary(dll);
return 0;
}