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

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 <cstdlib>
#include <iostream>
 
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 || result_2)
    {
        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