On Wed, Jan 05, 2022 at 01:56:26AM +0600, NRK wrote: > Just curious, why not use: > > #if defined(__has_builtin) && __has_builtin(__builtin_expect) > #define likely(expr) __builtin_expect(!!(expr), 1) > #define unlikely(expr) __builtin_expect(!!(expr), 0) > #else > #define likely(expr) (expr) > #define unlikely(expr) (expr) > #endif
Answering my own question: because it fails if `__has_builtin` is not defined. I was expecting the 2nd expression wouldn't get evaluated at all. Should probably take some time and learn more about the pre-processor sometimes. - NRK
