[except.special]

14.6.1 General [except.special.general]

The function std::terminate ([except.terminate]) is used by the exception handling mechanism for coping with errors related to the exception handling mechanism itself.

The function std::current_exception() and the class std::nested_exception can be used by a program to capture the currently handled exception.

14.6.2 The std::terminate function [except.terminate]

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In some situations, exception handling is abandoned for less subtle error handling techniques.

[Note 1:

These situations are:

(1.1)
when the exception handling mechanism, after completing the initialization of the exception object but before activation of a handler for the exception ([except.throw]), calls a function that exits via an exception, or
(1.2)
when the exception handling mechanism cannot find a handler for a thrown exception ([except.handle]), or
(1.3)
when the search for a handler encounters the outermost block of a function with a non-throwing exception specification, or
(1.4)
when the destruction of an object during stack unwinding terminates by throwing an exception, or
(1.5)
when initialization of a non-block variable with static or thread storage duration ([basic.start.dynamic]) exits via an exception, or
(1.6)
when destruction of an object with static or thread storage duration exits via an exception ([basic.start.term]), or
(1.7)
when execution of a function registered with std::atexit or std::at_quick_exit exits via an exception ([support.start.term]), or
(1.8)
when a throw-expression ([expr.throw]) with no operand attempts to rethrow an exception and no exception is being handled ([except.throw]), or
(1.9)
when the function std::nested_exception::rethrow_nested is called for an object that has captured no exception ([except.nested]), or
(1.10)
when execution of the initial function of a thread exits via an exception ([thread.thread.constr]), or
(1.11)
for a parallel algorithm whose ExecutionPolicy specifies such behavior ([execpol.seq], [execpol.par], [execpol.parunseq]), when execution of an element access function ([algorithms.parallel.defns]) of the parallel algorithm exits via an exception ([algorithms.parallel.exceptions]), or
(1.12)
when the destructor or the move assignment operator is invoked on an object of type std::thread that refers to a joinable thread ([thread.thread.destr], [thread.thread.assign]), or
(1.13)
when a call to a wait(), wait_until(), or wait_for() function on a condition variable ([thread.condition.condvar], [thread.condition.condvarany]) fails to meet a postcondition, or
(1.14)
when a callback invocation exits via an exception when requesting stop on a std::stop_source or a std::inplace_stop_source ([stopsource.mem], [stopsource.inplace.mem]), or in the constructor of std::stop_callback or std::inplace_stop_callback ([stopcallback.cons], [stopcallback.inplace.cons]) when a callback invocation exits via an exception, or
(1.15)
when a run_loop object is destroyed that is still in the running state ([exec.run.loop]), or
(1.16)
when unhandled_stopped is called on a with_awaitable_senders<T> object ([exec.with.awaitable.senders]) whose continuation is not a handle to a coroutine whose promise type has an unhandled_stopped member function.

— end note]

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In such cases, the function std::terminate is invoked ([exception.terminate]).

In the situation where no matching handler is found, it is implementation-defined whether or not the stack is unwound before std::terminate is invoked.

In the situation where the search for a handler ([except.handle]) encounters the outermost block of a function with a non-throwing exception specification ([except.spec]), it is implementation-defined whether the stack is unwound, unwound partially, or not unwound at all before the function std::terminate is invoked.

In all other situations, the stack shall not be unwound before the function std::terminate is invoked.

An implementation is not permitted to finish stack unwinding prematurely based on a determination that the unwind process will eventually cause an invocation of the function std::terminate.

14.6.3 The std::uncaught_exceptions function [except.uncaught]

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An exception is considered uncaught after completing the initialization of the exception object until completing the activation of a handler for the exception ([except.handle]).

[Note 1:

As a consequence, an exception is considered uncaught during any stack unwinding resulting from it being thrown.

— end note]

If an exception is rethrown ([expr.throw], [propagation]), it is considered uncaught from the point of rethrow until the rethrown exception is caught.

The function std::uncaught_exceptions ([uncaught.exceptions]) returns the number of uncaught exceptions in the current thread.

14 Exception handling [except]

14.6 Special functions [except.special]

14.6.1 General [except.special.general]

14.6.2 The std::terminate function [except.terminate]

14.6.3 The std::uncaught_exceptions function [except.uncaught]

14 Exception handling [except]

14.6 Special functions [except.special]

14.6.1 General [except.special.general]

14.6.2 The std​::​terminate function [except.terminate]

14.6.3 The std​::​uncaught_exceptions function [except.uncaught]

14.6.2 The std::terminate function [except.terminate]

14.6.3 The std::uncaught_exceptions function [except.uncaught]