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std::set_terminate

From cppreference.com
< cpp‎ | error
 
 
Diagnostics library
 
Defined in header <exception>
(until C++11)
std::terminate_handler set_terminate( std::terminate_handler f ) noexcept;
(since C++11)

Makes f the new global terminate handler function and returns the previously installed std::terminate_handler . f shall terminate execution of the program without returning to its caller, otherwise the behavior is undefined.

This function is thread-safe. Every call to std::set_terminate synchronizes-with (see std::memory_order ) subsequent calls to std::set_terminate and std::get_terminate .

(since C++11)

[edit] Parameters

f - pointer to function of type std::terminate_handler , or null pointer

[edit] Return value

The previously-installed terminate handler, or a null pointer value if none was installed.

[edit] Example

Run this code
#include <cstdlib>
#include <exception>
#include <iostream>
 
int main()
{
 std::set_terminate([]()
 {
 std::cout << "Unhandled exception\n" << std::flush ;
 std::abort ();
 });
 throw 1;
}

Possible output:

Unhandled exception
bash: line 7: 7743 Aborted (core dumped) ./a.out

The terminate handler will also work for launched threads, so it can be used as an alternative to wrapping the thread function with a try/catch block. In the following example, since the exception is unhandled, std::terminate will be called.

Run this code
#include <iostream>
#include <thread>
 
void run()
{
 throw std::runtime_error ("Thread failure");
}
 
int main()
{
 try
 {
 std::thread t{run};
 t.join();
 return EXIT_SUCCESS ;
 }
 catch (const std::exception & ex)
 {
 std::cerr << "Exception: " << ex.what() << '\n';
 }
 catch (...)
 {
 std::cerr << "Unknown exception caught\n";
 }
 return EXIT_FAILURE ;
}

Possible output:

terminate called after throwing an instance of 'std::runtime_error'
 what(): Thread failure
Aborted (core dumped)

With the introduction of the terminate handler, the exception thrown from the non-main thread can be analyzed, and exit can be gracefully performed.

Run this code
#include <iostream>
#include <thread>
 
class foo
{
public:
 foo() { std::cerr << "foo::foo()\n"; }
 ~foo() { std::cerr << "foo::~foo()\n"; }
};
 
// Static object, expecting destructor on exit
foo f;
 
void run()
{
 throw std::runtime_error ("Thread failure");
}
 
int main()
{
 std::set_terminate([]()
 {
 try
 {
 std::exception_ptr eptr{std::current_exception ()};
 if (eptr)
 {
 std::rethrow_exception (eptr);
 }
 else
 {
 std::cerr << "Exiting without exception\n";
 }
 }
 catch (const std::exception & ex)
 {
 std::cerr << "Exception: " << ex.what() << '\n';
 }
 catch (...)
 {
 std::cerr << "Unknown exception caught\n";
 }
 std::exit (EXIT_FAILURE );
 });
 
 std::thread t{run};
 t.join();
}

Output:

foo::foo()
Exception: Thread failure
foo::~foo()

[edit] See also

function called when exception handling fails
(function) [edit]
obtains the current terminate_handler
(function) [edit]
the type of the function called by std::terminate
(typedef) [edit]
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