exit
perform normal program termination
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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 \c 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 \c 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 (3) 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.
Example 1
\code #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; } \endcode
RETURN VALUES
The exit and _Exit functions never return.