std::atexit

int atexit( /*c-atexit-handler*/* func );
int atexit( /*atexit-handler*/* func );

int atexit( /*c-atexit-handler*/* func ) noexcept;
int atexit( /*atexit-handler*/* func ) noexcept;

extern "C++" using /*atexit-handler*/ = void(); // exposition-only
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 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

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).

Example

#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;
}

returning from main
at exit #2
at exit #1

See also