Question

This question is a bit specific, but here goes: I’d like to use ZZipLib with SDL. (http://zziplib.sourceforge.net/) ZZipLib comes with a file called SDL_rwops_zzip.c that is specifically intended to make it easy to plug into SDL’s file calls. And I have in fact done this without trouble on the Mac.

The problem is on Windows it won’t compile. The code in question is from SDL_rwops_zzip.c:

#define SDL_RWOPS_ZZIP_DATA(_context) \
         ((_context)->hidden.unknown.data1)
#define SDL_RWOPS_ZZIP_FILE(_context)  (ZZIP_FILE*) \
         ((_context)->hidden.unknown.data1)

static int _zzip_seek(SDL_RWops *context, int offset, int whence) // line 30
{
    return zzip_seek(SDL_RWOPS_ZZIP_FILE(context), offset, whence);
}

The errors I get are:

SDL_rwops_zzip.c(31): warning C4028: formal parameter 1 different from declaration
SDL_rwops_zzip.c(31): warning C4028: formal parameter 3 different from declaration
SDL_rwops_zzip.c(31): warning C4029: declared formal parameter list different from definition
SDL_rwops_zzip.c(31): error C2491: ‘_read’ : definition of dllimport function not allowed

This Stack Overflow post gives some info on that error:
definition of dllimport function not allowed

but I really don’t understand what to do to resolve this error in this particular situation.

Answer 1

I solved the problem by recompiling zziplib using a built-from-scratch Visual Studio 10 Project (the upgraded visual studio 7 project did not produce a working library or .dll), and then by commenting out these lines in conf.h:

# if !__STDC__
#  ifndef _zzip_lseek
#  define _zzip_lseek _lseek
#  endif
#  ifndef _zzip_read
#  define _zzip_read _read
#  endif
#  ifndef _zzip_write
#  define _zzip_write _write
#  endif
#      if 0
#  ifndef _zzip_stat
#  define _zzip_stat _stat
#  endif
#      endif
# endif // !__STDC__
#endif

and this:

#  ifndef _zzip_lseek
#  define _zzip_lseek lseek
#  endif

#  ifndef _zzip_read
#  define _zzip_read  read
#  endif

#  ifndef _zzip_write
#  define _zzip_write  write
#  endif