register a function to be called on
function registers the given function to be called at
program exit, whether via
exit(3) or via return from the program's
Functions so registered are called in reverse order; no arguments are
passed. At least 32 functions can always be registered, and more are allowed
as long as sufficient memory can be allocated.
If a shared object is unloaded from process memory
using dlclose(3), then any functions registered by calling
from that shared object will be called in reverse order and unregistered.
Note that it is the source of the call to
that matters, not the source of the function that was registered.
is very difficult to use correctly without creating
exit(3)-time races. Unless absolutely necessary, please avoid using
atexit() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate the
- No memory was available to add the function to the list. The existing list of functions is unmodified.
atexit() function conforms to
The behavior when a shared object is unloaded is an extension to that standard.