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.

SEE ALSO

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

COLOPHON

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