on_exit(3)

NAME
on_exit - register a function to be called at normal process termination

LIBRARY
Standard C library (libc, -lc)

SYNOPSIS
#include <stdlib.h>

int on_exit(typeof(void (int, void *)) *function, void *arg);

    Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

on_exit():
    Since glibc 2.19:
        _DEFAULT_SOURCE
    glibc 2.19 and earlier:
        _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION
The on_exit() function registers the given function to be called at normal process termination, whether via exit(3) or via return from the program's main(). The function is passed the status argument given to the last call to exit(3) and the arg argument from on_exit().

The same function may be registered multiple times: it is called once for each registration.

When a child process is created via fork(2), it inherits copies of its parent's registrations. Upon a successful call to one of the exec(3) functions, all registrations are removed.

RETURN VALUE
The on_exit() function returns the value 0 if successful; otherwise, it returns a nonzero value.

ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value
 | Thread safety | MT-Safe

STANDARDS
None.

HISTORY
SunOS 4, glibc. Removed in Solaris (SunOS 5). Use the standard atexit(3) instead.

CAVEATS
By the time function is executed, stack (auto) variables may already have gone out of scope. Therefore, arg should not be a pointer to a stack variable; it may however be a pointer to a heap variable or a global variable.

SEE ALSO
_exit(2), atexit(3), exit(3)