std::atexit
From cppreference.com
| Defined in header <cstdlib>
|
||
| int atexit( /*c-atexit-handler*/* func ); int atexit( /*atexit-handler*/* func ); |
(1) | |
| extern "C++" using /*atexit-handler*/ = void(); // exposition-only extern "C" using /*c-atexit-handler*/ = void(); // exposition-only |
(2) | |
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.
Parameters
| func | - | pointer to a function to be called on normal program termination |
Return value
0 if the registration succeeds, nonzero value otherwise.
Notes
The two overloads are distinct because the types of the parameter func are distinct (language linkage is part of its type)
Exceptions
| (none) | (until C++11) |
| noexcept specification: noexcept |
(since C++11) |
Example
Run this code
#include <iostream> #include <cstdlib> void atexit_handler_1() { std::cout << "at exit #1\n"; } void atexit_handler_2() { std::cout << "at exit #2\n"; } int main() { const int result_1 = std::atexit(atexit_handler_1); const int result_2 = std::atexit(atexit_handler_2); if ((result_1 != 0) or (result_2 != 0)) { std::cerr << "Registration failed\n"; return EXIT_FAILURE; } std::cout << "returning from main\n"; return EXIT_SUCCESS; }
Output:
returning from main at exit #2 at exit #1
See also
| causes abnormal program termination (without cleaning up) (function) | |
| causes normal program termination with cleaning up (function) | |
| (C++11) |
causes quick program termination without completely cleaning up (function) |
| (C++11) |
registers a function to be called on quick_exit invocation (function) |