编译错误与CImg

问题描述

我第一次使用CImg库，我使用简单的测试程序（包括CImg.h）获得编译错误。这是为什么？如何解决此问题？

计划代码：

  #include ../headers/CImg.h
 using namespace cimg_library; 
 int main（）
 {
 return 0; 
} 
  

编译错误：

 在函数'FILE * cimg_library :: cimg :: fopen（const char *，const char *）'：
 5065 | error：'_fileno' scope 
在函数'int cimg_library :: cimg :: fseek（FILE *，INT_PTR，int）'：
 5093 |错误：'_fseeki64'未在此范围中声明
在函数' INT_PTR cimg_library :: cimg :: ftell（FILE *）'：
 5102 |错误：'_ftelli64'未在此范围内声明
  

这是在64位Windows 8.1的电脑上完成的。

命令：

  g ++。exe -Wall -fexceptions -g -std = c ++ 11 -cD：\informatics\Projects\image experiments \Rectangle to circle stretcher\sources\main.cpp-o obj\Debug\sources\main.o 
  

我试过这个没有 -std = c ++ 11 部分，我得到2错误，而不是3.我不会得到 5065 |错误：'_fileno'未在此作用域中声明。如果我用 -std = gnu ++ 11

替换它也会在我的笔记本电脑上尝试，它运行64位版本的Windows 7，并且同样发生。

到目前为止，我有一个工作，第一个错误，但没有其他两个。

解决方案

如果是CodeBlock 16.01 stdio.h 包含行

  #if __MSVCRT_VERSION__> = 0x800 
 _CRTIMP int __cdecl __MINGW_NOTHROW _fseek_nolock（FILE *，long，int）; 
 _CRTIMP long __cdecl __MINGW_NOTHROW _ftell_nolock（FILE *）; 
 
 _CRTIMP int __cdecl __MINGW_NOTHROW _fseeki64（FILE *，__int64，int）; 
 _CRTIMP __int64 __cdecl __MINGW_NOTHROW _ftelli64（FILE *）; 
 _CRTIMP int __cdecl __MINGW_NOTHROW _fseeki64_nolock（FILE *，__int64，int）; 
 _CRTIMP __int64 __cdecl __MINGW_NOTHROW _ftelli64_nolock（FILE *）; 
 #endif 
  

除非 __ MSVCRT_VERSION __ 至少为0x800，否则不会声明这些函数。以下可能工作（至少它对于CodeBlocks 16.01）

  #if defined（__ MINGW32__ ）
 #define __MSVCRT_VERSION__ 0x800 
 #define _WIN32_WINNT 0x0500 
 #endif 
 
 //如果需要
 // #define _fileno fileno 
 
 #includeCImg.h
  

如果 stdio.h 不包含 _fseeki64 和其他人的声明

• 使用CImg 1.6.9不使用 _fseeki64 ，


• 升级gcc / g ++或


• _fseeki64 （如果可以在某处找到）。

I am using the CImg library for the first time and I get compilation errors with a simple test program that just includes CImg.h. Why is that? How can I fix this?

Program code:

#include "../headers/CImg.h"
using namespace cimg_library;
int main()
{
    return 0;
}

Compilation errors:

In function 'FILE* cimg_library::cimg::fopen(const char*, const char*)':
5065|error: '_fileno' was not declared in this scope
In function 'int cimg_library::cimg::fseek(FILE*, INT_PTR, int)':
5093|error: '_fseeki64' was not declared in this scope
In function 'INT_PTR cimg_library::cimg::ftell(FILE*)':
5102|error: '_ftelli64' was not declared in this scope

This was done on a PC with a 64 bit Windows 8.1.

Command:

g++.exe -Wall -fexceptions -g -std=c++11  -c "D:\informatics\Projects\image experiments\Rectangle to circle stretcher\sources\main.cpp" -o obj\Debug\sources\main.o

I tried this without the -std=c++11 part and I get 2 errors instead of 3. I don't get 5065|error: '_fileno' was not declared in this scope. Same happens if I replace it with -std=gnu++11

I also tried it on my laptop, which runs a 64 bit version of windows 7, and the same happens there.

So far, I have a work around for the first error, but nothing for the other two.

解决方案

In case of CodeBlock 16.01 stdio.h contains lines

#if __MSVCRT_VERSION__ >= 0x800
_CRTIMP int __cdecl __MINGW_NOTHROW     _fseek_nolock (FILE*, long, int);
_CRTIMP long __cdecl __MINGW_NOTHROW    _ftell_nolock (FILE*);

_CRTIMP int __cdecl __MINGW_NOTHROW     _fseeki64 (FILE*, __int64, int);
_CRTIMP __int64 __cdecl __MINGW_NOTHROW _ftelli64 (FILE*);
_CRTIMP int __cdecl __MINGW_NOTHROW     _fseeki64_nolock (FILE*, __int64, int);
_CRTIMP __int64 __cdecl __MINGW_NOTHROW _ftelli64_nolock (FILE*);
#endif

i.e. those functions are not declared unless __MSVCRT_VERSION__ is at least 0x800. The following might work (at least it did for CodeBlocks 16.01)

#if defined(__MINGW32__)
#define __MSVCRT_VERSION__ 0x800
#define _WIN32_WINNT 0x0500
#endif

// if needed
// #define _fileno fileno

#include "CImg.h"

If stdio.h does not contain declaration for _fseeki64 and others, either

• Use CImg 1.6.9 that does not use _fseeki64,
• upgrade gcc/g++, or
• provide an own implementation for _fseeki64 (if such one can be found somewhere).

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