### 2.17 `exit`—end program execution

Synopsis

         #include <stdlib.h>
         void exit(int code);

Description
Use `exit` to return control from a program to the host operating environment. Use the argument code to pass an exit status to the operating environment: two particular values, `EXIT_SUCCESS` and `EXIT_FAILURE`, are defined in ``stdlib.h`' to indicate success or failure in a portable fashion.

`exit` does two kinds of cleanup before ending execution of your program. First, it calls all application-defined cleanup functions you have enrolled with `atexit`. Second, files and streams are cleaned up: any pending output is delivered to the host system, each open file or stream is closed, and files created by `tmpfile` are deleted.

Returns
`exit` does not return to its caller.

Portability
ANSI C requires `exit`, and specifies that `EXIT_SUCCESS` and `EXIT_FAILURE` must be defined.

Supporting OS subroutines required: `_exit`.