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Re: [RFC PATCH 51/52] Y2038: add RPC functions

Paul Eggert wrote:


   /* time_t is always 'long int' in the GNU C Library.  */
   #define TIME_T_MIN LONG_MIN
   #define TIME_T_MAX LONG_MAX

   static inline bool
   fits_in_time_t (__time64_t t)
   {
   #if 7 <= __GNUC__
     return !__builtin_add_overflow_p (t, 0, TIME_T_MAX);
   #endif
     return TIME_T_MIN <= t && t <= TIME_T_MAX;
   }


Marc Glisse suggested a simpler solution:

  static inline bool
  fits_in_time_t (__time64_t t)
  {
    return t == (time64_t) t;
  }
This is documented to work for GCC, something I had forgotten, and it generates better code for pre-7 GCC. See: 

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82170#c2
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