Manpages - on_exit.3

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

  #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

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.

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

For an explanation of the terms used in this section, see *attributes*(7).

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.

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.

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

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