sample code:
#include <stdio.h>
void main()
{
unsigned long p;
printf("%p\n", &p);
// 64bit compile check. -m64, -m32
//
#if __LP64__
printf("__LP64__ defined...\n");
#else
printf("__LP64__ not defined...\n");
#endif
printf("p's sizeof is %zu\n", sizeof(p));
}Note: gcc only.
output:
$ gcc -o bitmode_compile bitmode_compile.c -m64 && ./bitmode_compile
0x7ffe5fe59380
__LP64__ defined...
p's sizeof is 8
$ gcc -o bitmode_compile bitmode_compile.c -m32 && ./bitmode_compile
0xffbf1fb8
__LP64__ not defined...
p's sizeof is 4
original source: http://kaspyx.kr/78