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atexit(3c) [opensolaris man page]

atexit(3C)						   Standard C Library Functions 						atexit(3C)

NAME
atexit - register a function to run at process termination or object unloading SYNOPSIS
#include <stdlib.h> int atexit(void (*func)(void)); DESCRIPTION
The atexit() function registers the function pointed to by func to be called without arguments on normal termination of the program or when the object defining the function is unloaded. Normal termination occurs by either a call to the exit(3C) function or a return from main(). Object unloading occurs when a call to dlclose(3C) results in the object becoming unreferenced. The number of functions that may be registered with atexit() is limited only by available memory (refer to the _SC_ATEXIT_MAX argument of sysconf(3C)). After a successful call to any of the exec(2) functions, any functions previously registered by atexit() are no longer registered. On process exit, functions are called in the reverse order of their registration. On object unloading, any functions belonging to an unloadable object are called in the reverse order of their registration. RETURN VALUES
Upon successful completion, the atexit() function returns 0. Otherwise, it returns a non-zero value. ERRORS
The atexit() function may fail if: ENOMEM Insufficient storage space is available. USAGE
The functions registered by a call to atexit() must return to ensure that all registered functions are called. There is no way for an application to tell how many functions have already been registered with atexit(). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Safe | +-----------------------------+-----------------------------+ SEE ALSO
exec(2), dlclose(3C), exit(3C), sysconf(3C), attributes(5) SunOS 5.11 25 May 2001 atexit(3C)

Check Out this Related Man Page

ATEXIT(3)						     Linux Programmer's Manual							 ATEXIT(3)

NAME
atexit - register a function to be called at normal process termination SYNOPSIS
#include <stdlib.h> int atexit(void (*function)(void)); DESCRIPTION
The atexit() function registers the given function to be called at normal process termination, either via exit(3) or via return from the program's main(). Functions so registered are called in the reverse order of their registration; no arguments are passed. The same function may be registered multiple times: it is called once for each registration. POSIX.1-2001 requires that an implementation allow at least ATEXIT_MAX (32) such functions to be registered. The actual limit supported by an implementation can be obtained using sysconf(3). 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 atexit() function returns the value 0 if successful; otherwise it returns a nonzero value. CONFORMING TO
SVr4, 4.3BSD, C89, C99, POSIX.1-2001. NOTES
Functions registered using atexit() (and on_exit(3)) are not called if a process terminates abnormally because of the delivery of a signal. If one of the functions registered functions calls _exit(2), then any remaining functions are not invoked, and the other process termina- tion steps performed by exit(3) are not performed. POSIX.1-2001 says that the result of calling exit(3) more than once (i.e., calling exit(3) within a function registered using atexit()) is undefined. On some systems (but not Linux), this can result in an infinite recursion; portable programs should not invoke exit(3) inside a function registered using atexit(). The atexit() and on_exit(3) functions register functions on the same list: at normal process termination, the registered functions are invoked in reverse order of their registration by these two functions. POSIX.1-2001 says that the result is undefined if longjmp(3) is used to terminate execution of one of the functions registered atexit(). Linux notes Since glibc 2.2.3, atexit() (and on_exit(3)) can be used within a shared library to establish functions that are called when the shared library is unloaded. EXAMPLE
#include <stdio.h> #include <stdlib.h> #include <unistd.h> void bye(void) { printf("That was all, folks "); } int main(void) { long a; int i; a = sysconf(_SC_ATEXIT_MAX); printf("ATEXIT_MAX = %ld ", a); i = atexit(bye); if (i != 0) { fprintf(stderr, "cannot set exit function "); exit(EXIT_FAILURE); } exit(EXIT_SUCCESS); } SEE ALSO
_exit(2), exit(3), on_exit(3) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2008-12-05 ATEXIT(3)
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