ON_EXIT

Section: Linux Programmer's Manual (3)
Updated: 2019-08-02
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NAME

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

SYNOPSIS

#include <stdlib.h>

int on_exit(void (*function)(int , void *), 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
on_exit()	Thread safety	MT-Safe

CONFORMING TO

This function comes from SunOS 4, but is also present in glibc. It no longer occurs in Solaris (SunOS 5). Portable application should avoid this function, and use the standard atexit(3) instead.

NOTES

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.

COLOPHON

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