gnu printf

Using Gnu style printf and scanf

On Windows, format specifiers like "%llu" will not work for 64bit integers on XP or earlier. To mitigate this problem, use the __mingw_* versions instead, for example:

#include <stdio.h>

int main(){
  __mingw_printf("%lld",0x8fffffffLL);
  return 0;
}

Alternatively with the __USE_MINGW_ANSI_STDIO macro:

#define __USE_MINGW_ANSI_STDIO 1
#include <stdio.h>

int main(){
  printf("%lld",0x8fffffffLL);
  return 0;
}

User printf and scanf

Code such as:

#define __USE_MINGW_ANSI_STDIO 1
#include <stdio.h>

__attribute__((__format__ (printf, 2, 3))) int my_print(void *c, const char *s, ...){
  /* do something with c */
  return printf(s,arglist);
}

still produce warning even if using gnu style formatting, since GCC will assume printf MS style arguments on Windows. The workaround is to use the __MINGW_PRINTF_FORMAT macro:

#define __USE_MINGW_ANSI_STDIO 1
#include <stdio.h>

__attribute__((__format__ (__MINGW_PRINTF_FORMAT, 2, 3))) int my_print(void *c, const char *s, ...){
  /* do something with c */
  return printf(s,arglist);
}

The __MINGW_PRINTF_FORMAT macro will be set to the proper attribute to inform GCC of the correct format style.