exit

INTERFACE

#include <stdlib.h>
void exit ( int status )
void _Exit ( int status )

DESCRIPTION

The exit and _Exit functions terminate a process.

Before termination, exit performs the following functions in the order listed:

• Call the functions registered with the atexit function, in the reverse order of their registration.
• Flush all open output streams.
• Close all open streams.
• Unlink all files created with the tmpfile function.

The _Exit function terminates without calling the functions registered with the atexit function, and may or may not perform the other actions listed. Both functions make the low-order eight bits of the status argument available to a parent process which has called a wait-family function.

The C Standard defines the values 0, EXIT_SUCCESS, and EXIT_FAILURE as possible values of status. Cooperating processes may use other values; in a program which might be called by a mail transfer agent, the values described in sysexits may be used to provide more information to the parent process.

Note that exit does nothing to prevent bottomless recursion should a function registered using atexit itself call exit . Such functions must call _Exit instead (although this has other effects as well which may not be desired).

The code below should always exit with error code 0.

#include <stdio.h>
#include <stdlib.h>

void main()
{
  int a = 0;

  if (a == 1) 
    exit(1);
  else 
    exit(0);

  // this never gets to execute
  a = 1;
}

RETURN VALUES

The exit and _Exit functions never return.

SEE ALSO

atexit, tmpfile