std:: atexit
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Program termination | ||||||||||||||||||||||||||||||||||||
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Unreachable control flow | ||||||||||||||||||||||||||||||||||||
(C++23)
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Communicating with the environment | ||||||||||||||||||||||||||||||||||||
Signals | ||||||||||||||||||||||||||||||||||||
Signal types | ||||||||||||||||||||||||||||||||||||
Non-local jumps | ||||||||||||||||||||||||||||||||||||
Types | ||||||||||||||||||||||||||||||||||||
Defined in header
<cstdlib>
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(1) | ||
int
atexit
(
/* c-atexit-handler */
*
func
)
;
int atexit ( /* atexit-handler */ * func ) ; |
(until C++11) | |
int
atexit
(
/* c-atexit-handler */
*
func
)
noexcept
;
int atexit ( /* atexit-handler */ * func ) noexcept ; |
(since C++11) | |
extern
"C"
using
/* c-atexit-handler */
=
void
(
)
;
extern "C++" using /* atexit-handler */ = void ( ) ; |
(2) | ( 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
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(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
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(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).
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; }
Output:
Returning from main... At exit #2 At exit #1
See also
causes abnormal program termination (without cleaning up)
(function) |
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causes normal program termination with cleaning up
(function) |
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(C++11)
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causes quick program termination without completely cleaning up
(function) |
(C++11)
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registers a function to be called on
std::quick_exit
invocation
(function) |
C documentation
for
atexit
|