ISO C99 intypes.h：printf不为uint64_t打印十六进制值

Question

My code is this (main.c):

#include <inttypes.h>
#include <stdio.h>


int
main(int argc, char **argv)
{
 uint64_t n;

 n = UINT64_MAX;

 printf("%" PRIX64 " %" PRIu64 "\n", n, n);

 return 0;
}

The output of the program is this:

FFFFFFFFFFFFFFFF 18446744073709551615

But I am looking for this:

10000000000000000 18446744073709551615

I am using GCC (gcc -std=c99 main.c): gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5

Looking for an answer in google gave me this: http://bytes.com/topic/c/answers/565055-convert-64-integer-hex-octet-string

Now, I am lost. What am I doing wrong?

Answer 1

the value of UINT64_MAX should be 0xffffffffffffffff as that is the value of 64-bits all set. I don't understand why you expect 0x10000000000000000 (which requires 65-bits to represent ).

Also 18446744073709551615 in decimal is equal to 0xffffffffffffffff , so printf is doing the right thing.