#if #if defined #if !defined #elif defined #else #elif !defined #ifndef #define

#if __WORDSIZE == 64
typedef long int __quad_t;
typedef unsigned long int __u_quad_t;
#elif defined __GLIBC_HAVE_LONG_LONG
__extension__ typedef long long int __quad_t;
__extension__ typedef unsigned long long int __u_quad_t;
#else
typedef struct
{
    long __val[2];
} __quad_t;
typedef struct
{
    __u_long __val[2];
} __u_quad_t;
#endif