stdlib.h

The header file contains prototypes for functions that perform miscellaneous tasks. Some of them exist also in other header files. The important ones that exist only in this header file are:

    exit()    getenv()    putenv()
    rand()    srand()
    malloc()  free()

These functions include the following actions: exiting a program, looking at or modifying the "environment" strings, random number generation, and calling another shell while the current program is suspended.