Cgo找不到< iostream>之类的标准库. [英] Cgo can't find standard libraries like <iostream>

问题描述

我正在尝试在Go代码中包含C ++代码，但无法识别.

I'm trying to include C++ code in my Go code, but isn't recognized.

我首先想到它将其视为C代码并尝试(并失败)这样的编译方式，但实际上删除包含行可为我提供c ++错误疑难解答，例如错误:"cout"不是"std"的成员该代码可以使用g ++正确编译.

I first thought that it considers it as C code and try (and fail) to compile as such, but removing the include line actually gives me c++ error troubleshooting like this error: ‘cout’ is not a member of ‘std’ The code compiles correctly with g++.

我尝试添加-lstdc ++ LDLFLAG，并在CXXFLAG中添加到lib的路径，但这并没有改变.

I have tried to add the -lstdc++ LDLFLAG, and add the path to the lib in CXXFLAG but it doesn't change a thing.

我做了其他一些测试(都失败了)，但这是最小的测试.

I have made some other tests (and all fail) but this is the smallest one.

这是c ++文件

test.cpp

#include "test.hpp"
    int test() 
    {
        std::cout << "Hello, World! ";
        return 0;
    }

test.hpp 
#include <iostream>
int test() ;

这是我的go文件

//#cgo CXXFLAGS: -I/usr/lib/
//#cgo LDFLAGS: -L/usr/lib/ -lstdc++
//#include "test.hpp"
import "C"

func main() {
    C.test()
}

我使用 go build 进行编译，但我也尝试使用 env CGO_ENABLED CGO_CXXFLAGS =-std = c ++ 11" go build (env部分是fish具体)，并返回相同的错误.

I compile using go build but I have also tried to use env CGO_ENABLED CGO_CXXFLAGS="-std=c++11" go build (the env part is fish specific) and it returns the same error.

应该正确编译，但是我有 iostream:没有这样的文件或目录.

It's supposed to compile correctly, but instead I have iostream: No such file or directory.

我尝试按照注释中的建议添加 CFLAGS:-x c ++ ，编译器在正确的位置进行搜索，但又出现了另一个错误，从'void *'到'_cgo_96e70225d9dd_Cfunc_test(void*)::< unnamed struct> *'[-fpermissive] ，我不知道它是否与此新的flafg相关

EDIT : I tried to add CFLAGS: -x c++ as suggested in the comments, the compiler searches at the right place, but I get another error invalid conversion from ‘void*’ to ‘_cgo_96e70225d9dd_Cfunc_test(void*)::<unnamed struct>*’ [-fpermissive] and I don't know if it's related to this new flafg

推荐答案

cgo使得用Go封装C非常容易，但是C ++有点不同.您必须外部"C" 您要在C ++中使函数名称具有'C'的函数'链接，否则链接器将看不到该功能.因此，实际的问题出在C ++头文件中.如果因为它是一个库而无法更改C ++代码，则可能必须编写包装器(

cgo makes it very easy to wrap C with Go, but C++ is a bit different. You have to extern "C" the functions that you want to make a function-name in C++ have 'C' linkage, otherwise the linker won't see the function. So, the actual problem is in the C++ header file. If you can't change the C++ code because it's a library, you may have to write wrappers (example).

这将编译:

.
├── test.cpp
├── test.go
└── test.hpp

test.hpp

#ifdef __cplusplus
extern "C" {
#endif

    int test();
#ifdef __cplusplus
}
#endif

test.cpp

#include <iostream>
#include "test.hpp"
int test() {
    std::cout << "Hello, World! ";
    return 0;
}

test.go

package main

// #cgo CXXFLAGS: -I/usr/lib/
// #cgo LDFLAGS: -L/usr/lib/ -lstdc++
// #include "test.hpp"
import "C"

func main() {
    C.test()
}

将文件放在同一文件夹中，运行 go build

Put the files in the same folder, run go build

你好，世界！

这篇关于Cgo找不到&lt; iostream&gt;之类的标准库.的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！