# std::promise<R>::set_exception_at_thread_exit

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< cpp‎ | thread‎ | promise

void set_exception_at_thread_exit( std::exception_ptr p ); |  | (since C++11)

Stores the exception pointer `p` into the shared state without making the state ready immediately. The state is made ready when the current thread exits, after all variables with thread-local storage duration have been destroyed.

The operation behaves as though set_value, set_exception, set_value_at_thread_exit, and `set_exception_at_thread_exit` acquire a single mutex associated with the promise object while updating the promise object.

An exception is thrown if there is no shared state or the shared state already stores a value or exception.

Calls to this function do not introduce data races with calls to get_future (but they need not synchronize with each other).

### Parameters

p | - | exception pointer to store. The behavior is undefined if `p` is null.

### Return value

(none)

### Exceptions

std::future_error on the following conditions:

- *this has no shared state. The error category is set to `no_state`.

- The shared state already stores a value or exception. The error category is set to `promise_already_satisfied`.

### Example

| This section is incomplete Reason: no example

### See also

set_exception | sets the result to indicate an exception (public member function)

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