Compilation errors with CImg

Question

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?

Progra

Answer 1

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).