Russell, > If a platform has time_t the same size as a long and long long, does > it matter whether the printf uses "%ld" or "%lld" ? >From my first mail: > For GNU C this is "the same" as both are of 8 bytes, but clang > generates a warning like: "warning: format specifies type 'long' but > the argument has type 'time_t' (aka 'long long')". Clang warns that it's not OK, though I'm not sure why exactly. On 23/10/20 04:06, Russell Shaw wrote: > On 23/10/20 5:54 pm, Anatoli wrote: >> Russell, >> >> Thanks for your suggestion. The problem is, as I mentioned in the initial >> post, on amd64 sizeof(time_t) is always 8 bytes, as well as long and long >> long, so sizeof(time_t) == sizeof(long int) == sizeof(long long int). >> >> I've actually tried the following directly in configure.ac (for this test >> it's not needed to run a custom code): >> >> #if (SIZEOF_TIME_T == SIZEOF_LONG_LONG_INT) #define TIME_T_FMT "%lld" #elif >> (SIZEOF_TIME_T == SIZEOF_LONG) #define TIME_T_FMT "%ld" #else #error dont >> know what to use for TIME_T_FMT #endif >> >> But both checks are true so it makes no sense. >> >> I need something that would not depend on the size of the type. Not sure it's >> even possible. > I might be missing something simple because i got up too early. > > If a platform has time_t the same size as a long and long long, does it matter whether the printf uses "%ld" or "%lld" ? >
