解决“退出状态 3221225477”的 swig/cgo 调试问题

在使用 SWIG 将 C++ 代码与 Go 集成的过程中，我遇到了“退出状态 3221225477”的调试问题。经过调查，我发现该问题与在 C++ 库中包含“iostream”库有关。删除该库后，我能够访问“command_line.h”中的变量，但由于库中需要它，我无法直接将其删除。通过将编译器从 TDM-GCC 更改为 MinGW64，我解决了这个问题，并能够成功构建和使用我的库。

我使用 swig 与 golang 的集成来生成 cgo 文件。我正在链接 c++ 库和 go。

我已经安装了我的软件包： swig -go -cgo -c++ -intgosize 64 ./basic_host.i 和 go install ，一切顺利。 但是当我在这里启动我的主要示例时：

package main

import (
    "fmt"
    "mylib/basic_host"
)

func main() {
    fmt.println("hello")
    basic_host.printhelpandexit("test", 0)
    fmt.println("world!")
}

当我尝试启动它时，我得到 exit 状态 3221225477 并且我的打印问候甚至没有被考虑在内，看来我的程序甚至没有启动...我不知道如何处理这个问题调试工具甚至没有启动。

退出状态似乎与 nil 指针 ref 相关：请参阅此处，这肯定是由于 cgo 集成所致。 我在 windows 10 上使用 mingw 进行构建，在我的配置下：

swig -version
swig version 4.0.2
compiled with i686-w64-mingw32-g++ [i686-w64-mingw32]
configured options: +pcre

我的 swig 接口文件是这样的（basic_host.i）：

%module basic_host
%{
    #include <atomic>
    #include <map>
    #include <iostream>
    #include <memory>
    
    #include <mylib/mylib.hpp>
    #include "../../examples/basic_host/command_line.h"
    #include "../../examples/basic_host/command_line.cpp"
%}

%inline %{
    extern void printhelpandexit(const char* binary, unsigned int exitcode);
%}

这是生成的 go 文件（basic_host.go）：

/* ----------------------------------------------------------------------------
 * this file was automatically generated by swig (http://www.swig.org).
 * version 4.0.2
 *
 * this file is not intended to be easily readable and contains a number of
 * coding conventions designed to improve portability and efficiency. do not make
 * changes to this file unless you know what you are doing--modify the swig
 * interface file instead.
 * ----------------------------------------------------------------------------- */

// source: .\basic_host.i

package basic_host

/*
#define intgo swig_intgo
typedef void *swig_voidp;

#include <stdint.h>


typedef long long intgo;
typedef unsigned long long uintgo;



typedef struct { char *p; intgo n; } _gostring_;
typedef struct { void* array; intgo len; intgo cap; } _goslice_;


typedef _gostring_ swig_type_1;
extern void _wrap_swig_free_basic_host_5ddda8bb50543998(uintptr_t arg1);
extern uintptr_t _wrap_swig_malloc_basic_host_5ddda8bb50543998(swig_intgo arg1);
extern void _wrap_printhelpandexit_basic_host_5ddda8bb50543998(swig_type_1 arg1, swig_intgo arg2);
#undef intgo
*/
import "c"

import "unsafe"
import _ "runtime/cgo"
import "sync"


type _ unsafe.pointer



var swig_escape_always_false bool
var swig_escape_val interface{}


type _swig_fnptr *byte
type _swig_memberptr *byte


type _ sync.mutex

func swig_free(arg1 uintptr) {
    _swig_i_0 := arg1
    c._wrap_swig_free_basic_host_5ddda8bb50543998(c.uintptr_t(_swig_i_0))
}

func swig_malloc(arg1 int) (_swig_ret uintptr) {
    var swig_r uintptr
    _swig_i_0 := arg1
    swig_r = (uintptr)(c._wrap_swig_malloc_basic_host_5ddda8bb50543998(c.swig_intgo(_swig_i_0)))
    return swig_r
}

func printhelpandexit(arg1 string, arg2 uint) {
    _swig_i_0 := arg1
    _swig_i_1 := arg2
    c._wrap_printhelpandexit_basic_host_5ddda8bb50543998(*(*c.swig_type_1)(unsafe.pointer(&_swig_i_0)), c.swig_intgo(_swig_i_1))
    if swig_escape_always_false {
        swig_escape_val = arg1
    }
}

这是 c++ 包装文件 (basic_host_wrap.cxx)：

/* ----------------------------------------------------------------------------
 * this file was automatically generated by swig (http://www.swig.org).
 * version 4.0.2
 *
 * this file is not intended to be easily readable and contains a number of
 * coding conventions designed to improve portability and efficiency. do not make
 * changes to this file unless you know what you are doing--modify the swig
 * interface file instead.
 * ----------------------------------------------------------------------------- */

// source: .\basic_host.i

#define swigmodule basic_host

#ifdef __cplusplus
/* swigvaluewrapper is described in swig.swg */
template<typename t> class swigvaluewrapper {
  struct swigmovepointer {
    t *ptr;
    swigmovepointer(t *p) : ptr(p) { }
    ~swigmovepointer() { delete ptr; }
    swigmovepointer& operator=(swigmovepointer& rhs) { t* oldptr = ptr; ptr = 0; delete oldptr; ptr = rhs.ptr; rhs.ptr = 0; return *this; }
  } pointer;
  swigvaluewrapper& operator=(const swigvaluewrapper<t>& rhs);
  swigvaluewrapper(const swigvaluewrapper<t>& rhs);
public:
  swigvaluewrapper() : pointer(0) { }
  swigvaluewrapper& operator=(const t& t) { swigmovepointer tmp(new t(t)); pointer = tmp; return *this; }
  operator t&() const { return *pointer.ptr; }
  t *operator&() { return pointer.ptr; }
};

template <typename t> t swigvalueinit() {
  return t();
}
#endif

/* -----------------------------------------------------------------------------
 *  this section contains generic swig labels for method/variable
 *  declarations/attributes, and other compiler dependent labels.
 * ----------------------------------------------------------------------------- */

/* template workaround for compilers that cannot correctly implement the c++ standard */
#ifndef swigtemplatedisambiguator
# if defined(__sunpro_cc) && (__sunpro_cc <= 0x560)
#  define swigtemplatedisambiguator template
# elif defined(__hp_acc)
/* needed even with `acc -aa' when `acc -v' reports hp ansi c++ b3910b a.03.55 */
/* if we find a maximum version that requires this, the test would be __hp_acc <= 35500 for a.03.55 */
#  define swigtemplatedisambiguator template
# else
#  define swigtemplatedisambiguator
# endif
#endif

/* inline attribute */
#ifndef swiginline
# if defined(__cplusplus) || (defined(__gnuc__) && !defined(__strict_ansi__))
#   define swiginline inline
# else
#   define swiginline
# endif
#endif

/* attribute recognised by some compilers to avoid 'unused' warnings */
#ifndef swigunused
# if defined(__gnuc__)
#   if !(defined(__cplusplus)) || (__gnuc__ > 3 || (__gnuc__ == 3 && __gnuc_minor__ >= 4))
#     define swigunused __attribute__ ((__unused__))
#   else
#     define swigunused
#   endif
# elif defined(__icc)
#   define swigunused __attribute__ ((__unused__))
# else
#   define swigunused
# endif
#endif

#ifndef swig_msc_unsuppress_4505
# if defined(_msc_ver)
#   pragma warning(disable : 4505) /* unreferenced local function has been removed */
# endif
#endif

#ifndef swigunusedparm
# ifdef __cplusplus
#   define swigunusedparm(p)
# else
#   define swigunusedparm(p) p swigunused
# endif
#endif

/* internal swig method */
#ifndef swigintern
# define swigintern static swigunused
#endif

/* internal inline swig method */
#ifndef swiginterninline
# define swiginterninline swigintern swiginline
#endif

/* exporting methods */
#if defined(__gnuc__)
#  if (__gnuc__ >= 4) || (__gnuc__ == 3 && __gnuc_minor__ >= 4)
#    ifndef gcc_hasclassvisibility
#      define gcc_hasclassvisibility
#    endif
#  endif
#endif

#ifndef swigexport
# if defined(_win32) || defined(__win32__) || defined(__cygwin__)
#   if defined(static_linked)
#     define swigexport
#   else
#     define swigexport __declspec(dllexport)
#   endif
# else
#   if defined(__gnuc__) && defined(gcc_hasclassvisibility)
#     define swigexport __attribute__ ((visibility("default")))
#   else
#     define swigexport
#   endif
# endif
#endif

/* calling conventions for windows */
#ifndef swigstdcall
# if defined(_win32) || defined(__win32__) || defined(__cygwin__)
#   define swigstdcall __stdcall
# else
#   define swigstdcall
# endif
#endif

/* deal with microsoft's attempt at deprecating c standard runtime functions */
#if !defined(swig_no_crt_secure_no_deprecate) && defined(_msc_ver) && !defined(_crt_secure_no_deprecate)
# define _crt_secure_no_deprecate
#endif

/* deal with microsoft's attempt at deprecating methods in the standard c++ library */
#if !defined(swig_no_scl_secure_no_deprecate) && defined(_msc_ver) && !defined(_scl_secure_no_deprecate)
# define _scl_secure_no_deprecate
#endif

/* deal with apple's deprecated 'assertmacros.h' from carbon-framework */
#if defined(__apple__) && !defined(__assert_macros_define_versions_without_underscores)
# define __assert_macros_define_versions_without_underscores 0
#endif

/* intel's compiler complains if a variable which was never initialised is
 * cast to void, which is a common idiom which we use to indicate that we
 * are aware a variable isn't used.  so we just silence that warning.
 * see: https://github.com/swig/swig/issues/192 for more discussion.
 */
#ifdef __intel_compiler
# pragma warning disable 592
#endif


#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>



typedef long long intgo;
typedef unsigned long long uintgo;


# if !defined(__clang__) && (defined(__i386__) || defined(__x86_64__))
#   define swigstructpacked __attribute__((__packed__, __gcc_struct__))
# else
#   define swigstructpacked __attribute__((__packed__))
# endif



typedef struct { char *p; intgo n; } _gostring_;
typedef struct { void* array; intgo len; intgo cap; } _goslice_;




#define swiggo_size_assert_eq(x, y, name) typedef char name[(x-y)*(x-y)*-2+1];
#define swiggo_size_assert(t, n) swiggo_size_assert_eq(sizeof(t), n, swiggo_sizeof_##t##_is_not_##n)

swiggo_size_assert(char, 1)
swiggo_size_assert(short, 2)
swiggo_size_assert(int, 4)
typedef long long swiggo_long_long;
swiggo_size_assert(swiggo_long_long, 8)
swiggo_size_assert(float, 4)
swiggo_size_assert(double, 8)

#ifdef __cplusplus
extern "c" {
#endif
extern void crosscall2(void (*fn)(void *, int), void *, int);
extern char* _cgo_topofstack(void) __attribute__ ((weak));
extern void _cgo_allocate(void *, int);
extern void _cgo_panic(void *, int);
#ifdef __cplusplus
}
#endif

static char *_swig_topofstack() {
  if (_cgo_topofstack) {
    return _cgo_topofstack();
  } else {
    return 0;
  }
}

static void _swig_gopanic(const char *p) {
  struct {
    const char *p;
  } swigstructpacked a;
  a.p = p;
  crosscall2(_cgo_panic, &a, (int) sizeof a);
}




#define swig_contract_assert(expr, msg) \
  if (!(expr)) { _swig_gopanic(msg); } else


static void swig_free(void* p) {
  free(p);
}

static void* swig_malloc(int c) {
  return malloc(c);
}


    #include <atomic>
    #include <map>
    #include <iostream>
    #include <memory>
    
    #include <mylib/mylib.hpp>
    #include "../../examples/basic_host/command_line.h"
    #include "../../examples/basic_host/command_line.cpp"


    extern void printhelpandexit(const char* binary, unsigned int exitcode);

#ifdef __cplusplus
extern "c" {
#endif

void _wrap_swig_free_basic_host_5ddda8bb50543998(void *_swig_go_0) {
  void *arg1 = (void *) 0 ;
  
  arg1 = *(void **)&_swig_go_0; 
  
  swig_free(arg1);
  
}


void *_wrap_swig_malloc_basic_host_5ddda8bb50543998(intgo _swig_go_0) {
  int arg1 ;
  void *result = 0 ;
  void *_swig_go_result;
  
  arg1 = (int)_swig_go_0; 
  
  result = (void *)swig_malloc(arg1);
  *(void **)&_swig_go_result = (void *)result; 
  return _swig_go_result;
}


void _wrap_printhelpandexit_basic_host_5ddda8bb50543998(_gostring_ _swig_go_0, intgo _swig_go_1) {
  char *arg1 = (char *) 0 ;
  unsigned int arg2 ;
  
  
  arg1 = (char *)malloc(_swig_go_0.n + 1);
  memcpy(arg1, _swig_go_0.p, _swig_go_0.n);
  arg1[_swig_go_0.n] = '\0';
  
  arg2 = (unsigned int)_swig_go_1; 
  
  printhelpandexit((char const *)arg1,arg2);
  
  free(arg1); 
}


#ifdef __cplusplus
}
#endif

cpp printhelpandexit 中的函数：

void printHelpAndExit(const char* binary, unsigned int exitCode)
{
    std::cout << "Usage: " << binary
            << " -t test " << std::endl;
    std::cout << std::endl;
    std::cout << " -h                          Prints this help and exit" << std::endl;
    std::cout << " -t test                    test desc "
            "desc."
            << std::endl;
    exit(exitCode);
}

如果您对构建问题有任何想法或调试可能导致此问题的原因。我很高兴听到这个消息。

更新#1：

我发现，如果删除 lib ，我就可以毫无问题地访问 "../../examples/basic_host/command_line.h" 的变量。我仍然不知道为什么这个库特别引起问题，但我正在调查它。顺便说一句，我不能直接删除它，因为我的 c++ 库中需要它。

我发现另一个人用 python 构建 c++ 并与我使用 iostream 遇到相同的问题，但没有解释如何做到这一点：

更新#2：

似乎它来自我的编译器，我目前正在使用 tdm gcc，并且在 windows 下出现错误。我尝试使用 wsl2 ubuntu 进行编译并且它可以工作。不过，我仍然需要在 windows 下构建，因为我在库中使用 winsock。

解决方案

我遇到的问题是我在 Windows 上使用的编译器。我曾经用 TDM-GCC 进行编译，但它和 iostreamlib 之间存在已知问题，如 this post suggests...

我刚刚将使用 SWIG 构建的编译器（gcc、g++、..）更改为 MinGW64：download link。之后一切正常，我可以毫无问题地使用我的库。 感谢那些试图帮助我的人。

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