2.13.1 Variables and Definitions

size_t is the unsigned integer result of the sizeof keyword.
wchar_t is an integer type of the size of a wide character constant.
div_t is the structure returned by the div function.
ldiv_t is the structure returned by the ldiv function.

NULL is the value of a null pointer constant.
EXIT_FAILURE and EXIT_SUCCESS are values for the exit function to return termination status.
RAND_MAX is the maximum value returned by the rand function.
MB_CUR_MAX is the maximum number of bytes in a multibyte character set which cannot be larger than MB_LEN_MAX.