| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
| .\" preserved on all copies. |
| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
| .\" professionally. |
| .\" |
| .\" Formatted or processed versions of this manual, if unaccompanied by |
| .\" the source, must acknowledge the copyright and authors of this work. |
| .\" %%%LICENSE_END |
| .\" |
| .\" References consulted: |
| .\" Linux libc source code |
| .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) |
| .\" 386BSD man pages |
| .\" Modified 1993-04-02, David Metcalfe |
| .\" Modified 1993-07-25, Rik Faith (faith@cs.unc.edu) |
| .TH ON_EXIT 3 2021-03-22 "GNU" "Linux Programmer's Manual" |
| .SH NAME |
| on_exit \- register a function to be called at normal process termination |
| .SH SYNOPSIS |
| .nf |
| .B #include <stdlib.h> |
| .PP |
| .BI "int on_exit(void (*" function ")(int , void *), void *" arg ); |
| .fi |
| .PP |
| .RS -4 |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .RE |
| .PP |
| .BR on_exit (): |
| .nf |
| Since glibc 2.19: |
| _DEFAULT_SOURCE |
| Glibc 2.19 and earlier: |
| _BSD_SOURCE || _SVID_SOURCE |
| .fi |
| .SH DESCRIPTION |
| The |
| .BR on_exit () |
| function registers the given |
| .I function |
| to be |
| called at normal process termination, whether via |
| .BR exit (3) |
| or via return from the program's |
| .IR main (). |
| The |
| .I function |
| is passed the status argument given to the last call to |
| .BR exit (3) |
| and the |
| .I arg |
| argument from |
| .BR on_exit (). |
| .PP |
| The same function may be registered multiple times: |
| it is called once for each registration. |
| .PP |
| When a child process is created via |
| .BR fork (2), |
| it inherits copies of its parent's registrations. |
| Upon a successful call to one of the |
| .BR exec (3) |
| functions, all registrations are removed. |
| .SH RETURN VALUE |
| The |
| .BR on_exit () |
| function returns the value 0 if successful; otherwise |
| it returns a nonzero value. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR on_exit () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH 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 |
| .BR atexit (3) |
| instead. |
| .SH NOTES |
| By the time |
| .I function |
| is executed, stack |
| .RI ( auto ) |
| variables may already have gone out of scope. |
| Therefore, |
| .I arg |
| should not be a pointer to a stack variable; |
| it may however be a pointer to a heap variable or a global variable. |
| .SH SEE ALSO |
| .BR _exit (2), |
| .BR atexit (3), |
| .BR exit (3) |