21 Language support library [language.support]

21.8 Exception handling [support.exception]

21.8.5 uncaught_­exceptions [uncaught.exceptions]

int uncaught_exceptions() noexcept;

Returns: Количество uncaught exceptions.

Remarks: Когда uncaught_­exceptions() > 0выброс исключения может привести к вызову std​::​terminate().