ATEXIT(3) BSD Library Functions Manual ATEXIT(3)NAME
atexit — register a function to be called on exit
The atexit() function registers the function func to be called at program
exit, whether via exit(3) or via return from the program's main(). Func‐
tions so registered are called in reverse order; no arguments are passed.
The atexit_b() function is like atexit() except the callback is a block
pointer instead of a function pointer.
Note: The Block_copy() function (defined in <Blocks.h>) is used by
atexit_b() to make a copy of the block, especially for the case
when a stack-based block might go out of scope when the subroutine
These callbacks must not call exit(); if it should be necessary to termi‐
nate the process while in such a function, the _exit(2) function should
be used. (Alternatively, the callbacks may cause abnormal process termi‐
nation, for example by calling abort(3).)
At least 32 callbacks can always be registered; more are allowed as long
as sufficient memory can be allocated.
The atexit() and atexit_b() functions return the value 0 if successful;
otherwise the value -1 is returned and the global variable errno is set
to indicate the error.
[ENOMEM] No memory was available to add the function to the
list. The existing list of functions is unmodified.
The atexit() function conforms to ISO/IEC 9899:1990 (“ISO C90”).
BSD May 20, 2008 BSD