function registers the given function to be
called at normal process termination, whether via
or via return from the program's main().
The function is passed the status argument given to the last call to
and the arg argument from
The same function may be registered multiple times:
it is called once for each registration.
When a child process is created via
it inherits copies of its parent's registrations.
Upon a successful call to one of the
functions, all registrations are removed.
function returns the value 0 if successful; otherwise
it returns a nonzero value.
This function comes from SunOS 4, but is also present in
libc4, libc5 and glibc.
It no longer occurs in Solaris (SunOS 5).
Avoid this function, and use the standard