/*-
 * file: int64.c
 * auth: mymtom
 * date: 2008-08-19
 */

#include <sys/types.h>
#include <stdio.h>

int
main(void)
{
        long long       nLL = 0x1111222233334444LL;
        int64_t         n64 = 0x5555666677778888LL;

        (void)printf("%llx\n", nLL);
        (void)printf("%llx\n", n64);

        return (0);
}

------解决方案--------------------
你用的就是64位，只不过你当32为打印出来。

要去掉warning:
man gcc
      -Wlong-long
          Warn if long long type is used.  This is default.  To inhibit the
          warning messages, use -Wno-long-long.  Flags -Wlong-long and
          -Wno-long-long are taken into account only when -pedantic flag is
          used.