std::uncaught_exception

 

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Defined in header <exception>
bool uncaught_exception();

Detects if the current thread has a live exception object, that is, an exception has been thrown and not yet entered a matching catch clause, std::terminate or std::unexpected. In other words, stack unwinding is currently in progress.

Any exception thrown while std::uncaught_exception() == true calls std::terminate.

Parameters

(none)

Return value

true if stack unwinding is currently in progress in this thread.

Exceptions

noexcept specification:  

noexcept

  (since C++11)

Example

#include <iostream>
#include <exception>
#include <stdexcept>
struct Foo {
    ~Foo() {
        if(std::uncaught_exception())
            std::cout << "~Foo() called during stack unwinding\n";
        else
            std::cout << "~Foo() called normally\n";
    }
};
int main()
{
    Foo f;
    try {
        Foo f;
        std::cout << "Exception thrown\n";
        throw std::runtime_error("test exception");
    } catch(const std::exception& e) {
        std::cout << "Exception caught: " << e.what() << '\n';
    }
}

Output:

Exception thrown
~Foo() called during stack unwinding
Exception caught: test exception
~Foo() called normally

See also

terminate	function called when exception handling fails (function)
exception_ptr (C++11)	shared pointer type for handling exception objects (typedef)

External links

GOTW issue 47: Uncaught Exceptions