std::atexit (3) - Linux Manuals
Defined in header <cstdlib>
int atexit( /*c-atexit-handler*/* func ); (until C++11)
int atexit( /*atexit-handler*/* func );
int atexit( /*c-atexit-handler*/* func ) noexcept; (1) (since C++11)
int atexit( /*atexit-handler*/* func ) noexcept;
extern "C++" using /*atexit-handler*/ = void(); // exposition-only (2)
extern "C" using /*c-atexit-handler*/ = void(); // exposition-only
Registers the function pointed to by func to be called on normal program termination (via std::exit() or returning from the main_function)
The functions will be called during the destruction of the static objects, in reverse order: if A was registered before B, then the call to B is made before the call to A. Same applies to the ordering between static object constructors and the calls to atexit: see std::exit (until C++11)
The functions may be called concurrently with the destruction of the objects with static storage duration and with each other, maintaining the guarantee that if registration of A was sequenced-before the registration of B, then the call to B is sequenced-before the call to A, same applies to the sequencing between static object constructors and calls to atexit: see std::exit (since C++11)
The same function may be registered more than once.
If a function exits via an exception, std::terminate is called.
atexit is thread-safe: calling the function from several threads does not induce a data race.
The implementation is guaranteed to support the registration of at least 32 functions. The exact limit is implementation-defined.
func - pointer to a function to be called on normal program termination
0 if the registration succeeds, nonzero value otherwise.
The two overloads are distinct because the types of the parameter func are distinct (language_linkage is part of its type)
// Run this code
quick_exit causes quick program termination without completely cleaning up
at_quick_exit registers a function to be called on quick_exit invocation