INT01-C. Use rsize_t or size_t for all integer values representing the size of an object

The size_t type is the unsigned integer type of the result of the sizeof operator. Variables of type size_t are guaranteed to be of sufficient precision to represent the size of an object. The limit of size_t is specified by the SIZE_MAX macro.

The type size_t generally covers the entire address space. ISO/IEC TR 24731-1:2007 introduces a new type rsize_t, defined to be size_t but explicitly used to hold the size of a single object. In code that documents this purpose by using the type rsize_t, the size of an object can be checked to verify that it is no larger than RSIZE_MAX, the maximum size of a normal single object, which provides additional input validation for library functions. See STR07-C, “Use TR 24731 for remediation of existing string manipulation code,” for additional discussion of TR 24731-1.