Gunther Nikl <gnikl@xxxxxxxxxxxxxxxxxxxxx> writes: > Ian Lance Taylor wrote: >> Gunther Nikl <gnikl@xxxxxxxxxxxxxxxxxxxxx> writes: >> >>> Here is an example for int_fast8_t: >>> >>> typedef signed char int_fast8_t; >>> #define INT_FAST8_MIN INT8_MIN >>> #define INT_FAST8_MAX INT8_MAX >>> >>> Now if int_fast8_t uses "int" as underlying type like this: >>> >>> typedef int int_fast8_t; >>> >>> which value is its MIN/MAX macros supposed to have? Is it >>> allowed to use the same "char" limits as above or do I need >>> to use >>> >>> #define INT_FAST8_MIN INT32_MIN >>> #define INT_FAST8_MAX INT32_MAX >>> >>> in that case? >>> >>> So this is not about user code but an implementation question. >> >> The value of INT_FAST8_MIN is implementation defined, so you can choose >> whatever value you like (as long as it is <= -128). That said, the >> standard seems to suggest that the value should correspond to the value >> of the underlying type. That is, if int_fast8_t is defined as int, then >> the value of INT_FAST8_MIN should be INT_MIN. That at least makes >> INT_FAST8_MIN useful, as otherwise it would always simply have the >> value -128. > > Thanks for the information about the standard. FWIW, I assumed that if > a fast 8bit type was requested than its only about a 8bit value range > and thus the 8bit limits are sufficient. Yes, it's hard to understand why a program would ever want to test INT_FAST8_MIN. I tried Google CodeSearch but it could only find definitions, not uses. Ian
