stdlib.h

The stdlib.h header file contains declarations for the following functions.

abs()¹

atoi()

atol()

atoll()

calloc()

div()

free()

labs()

ldiv()

llabs()

lldiv()

malloc()

__malloc31()

qsort()

rand()

rand_r()

realloc()

srand()

strtod()

strtof()

strtol()

strtold()

strtoll()

strtoul()

strtoull()

¹ Built-in function.

Two type definitions are added to stdlib.h for the Compare and Swap functions cs() and cds(). The structures defined are cs_t and cds_t.

The type size_t is declared in the header file. It is used for the type of the value returned by sizeof. For more information on the types size_t, see stddef.h.

The stdlib.h declares div_t, ldiv_t, and lldiv_t, which define the structure types that are returned by div(), ldiv(), and lldiv().

The stdlib.h file also contains definitions for the following macros:

NULL: The NULL pointer constant (also defined in stddef.h).
RAND_MAX: Expands to an integer representing the largest number that the rand() or rand_r() function can return.