c++ - 在macOS主机上与Windows目标的cgo交叉编译golang

我在macOS上，尝试使用从自制软件安装的mingw-w64交叉编译Windows的golang(CGO 1.10)可执行文件。

我有只带有一个函数(SimpleQRDecode)的golang软件包，该函数从我的c++源代码(FindAndDecodeQR，使用zxing c++端口)调用其他函数。

编译ZXing源代码很好(x86_64-w64-mingw32-g++)

编译qrcode.cpp很好(x86_64-w64-mingw32-g++)

成功将所有对象(zxing + my)合并到静态库(x86_64-w64-mingw32-ar)

在静态库(x86_64-w64-mingw32-ranlib)上成功调用ranlib

失败调用CGO_ENABLED=1 CXX="x86_64-w64-mingw32-g++" CXX_FOR_TARGET="x86_64-w64-mingw32-g++" CC="x86_64-w64-mingw32-gcc" CC_FOR_TARGET="x86_64-w64-mingw32-gcc" GOOS=windows GOARCH=amd64 go build -x

go build输出包含大量未解析的符号消息，例如

libmyqr.a(qrcode.o):qrcode.cpp:(.text+0x79): undefined reference to `operator new(unsigned long long)'
libmyqr.a(qrcode.o):qrcode.cpp:(.text+0x2cb): undefined reference to `std::string::length() const'
libmyqr.a(qrcode.o):qrcode.cpp:(.text+0x4a7): undefined reference to `__cxa_begin_catch'
libmyqr.a(BinaryBitmap.cpp.obj):BinaryBitmap.cpp:(.text+0x5c2): undefined reference to `std::ios_base::Init::~Init()'
libmyqr.a(BinaryBitmap.cpp.obj):BinaryBitmap.cpp:(.xdata+0xc): undefined reference to `__gxx_personality_seh0'

qrcode.go:

package qrcode

/*
#cgo CFLAGS: -I../../native/prefix/include -I../../libmyqr -fPIC
#cgo CXXFLAGS: -I../../native/prefix/include -I../../libmyqr -fPIC
#cgo LDFLAGS: -L../../libmyqr -lmyqr -lstdc++
#include <stdlib.h>
#include <qrcode.h>
*/
import "C"

import (
    "errors"
    "fmt"
    "unsafe"
)

func SimpleQRDecode(rasterData []byte, width, height int) (string, bool, error) {
    res := C.FindAndDecodeQR((*C.char)(unsafe.Pointer(&data[0])), C.int(len(data)), C.int(width), C.int(height))

qrcode.h:

#ifdef __cplusplus
extern "C" {
#endif

const char* FindAndDecodeQR(char *raster, int size, int width, int height);


#ifdef __cplusplus
}
#endif

qrcode.cpp:

#include "qrcode.h"

#include <sstream>

#include <zxing/ZXing.h>
#include <zxing/Binarizer.h>
#include <zxing/BinaryBitmap.h>
#include <zxing/Result.h>
#include <zxing/qrcode/QRCodeReader.h>
#include <zxing/common/GreyscaleRotatedLuminanceSource.h>
#include <zxing/common/GlobalHistogramBinarizer.h>

const char* FindAndDecodeQR(char *raster, int size, int width, int height) {
    // GreyscaleLuminanceSource

    std::ostringstream resStream;

    try {
        zxing::ArrayRef<char> image(raster, size);
        zxing::Ref<zxing::GreyscaleRotatedLuminanceSource> source(new zxing::GreyscaleRotatedLuminanceSource(image, width, height, 0, 0, width, height));

libmyqr.a-由所有zxing编译对象+ qrcode.cpp.o组成的静态库

最佳答案

可能不是您想听到的，但在Mac上交叉编译到Windows的最简单方法是从c/c++代码构建DLL库，并从go代码处理此DLL库。在这种情况下，您甚至不需要CGO_ENABLED=1。
go代码如下所示(未经测试):

// +build windows

package qrcode

import (
    "errors"
    "fmt"
    "syscalls"
    "unsafe"
)

var modYourPkg = syscall.NewLazyDLL("yourpkg.dll")

var procFindAndDecodeQR = modYourPkg.NewProc("FindAndDecodeQR")

func SimpleQRDecode(rasterData []byte, width, height int) (string, bool, error) {
    res, _, _ := procFindAndDecodeQR.Call(
        uintptr(unsafe.Pointer(&rasterData[0])),
        uintptr(len(data)),
        uintptr(width),
        uintptr(height),
    )
    ...
}

有关syscall软件包的更多信息，请参见。

关于c++ - 在macOS主机上与Windows目标的cgo交叉编译golang，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/49492589/