printf - warning: long long int format, int64_t arg

Method 1：

头文件<stdint.h>下：

# if __WORDSIZE == 64
typedef long int  int64_t;
# else
__extension__
typedef long long int  int64_t;
# endif

可以像头文件定义那样，判断宏，然后选择对应的输出格式：

#include <stdio.h>
#include <stdlib.h>

int main()
{
int64_t test = 16;
# if __WORDSIZE == 64
printf("%ld\n", test);
# else
__extension__
printf("%lld\n", test);
# endif
return 0;
}

Method 2：

头文件inttypes.h下：/* The ISO C99 standard specifies that these macros must only bedefined if explicitly requested. */#if !defined __cplusplus || defined __STDC_FORMAT_MACROS# if __WORDSIZE == 64# define __PRI64_PREFIX "l"# define __PRIPTR_PREFIX "l"# else# define __PRI64_PREFIX "ll"# define __PRIPTR_PREFIX# endif/* Macros for printing format specifiers. *//* Decimal notation. */# define PRId8 "d"# define PRId16 "d"# define PRId32 "d"# define PRId64 __PRI64_PREFIX "d"所以

int64_t

类型:

int64_t t;printf("%" PRId64 "\n", t);

for

uint64_t

type:

uint64_t t;printf("%" PRIu64 "\n", t);

you can also use

PRIx64

to print in hexadecimal.These macros are defined in

inttypes.h