Constant Macros

Use the macros INT8_C(c), …, INT64_C(c), UINT8_C(c),…, UINT64_C(c) to specify the size and sign of a given constant. Basically, these macros place an l, ul, ll, or ull at the end of the constant, if necessary. For example, INT64_C(1) appends ll to the constant 1 for ILP32 and an l for LP64.

Use the INTMAX_C(c) and UINTMAX_C(c) macros to make a constant the biggest type. These macros can be very useful for specifying the type of constants described in 7.3 Converting to the LP64 Data Type Model.