Why does cancelling a pthread in an IO function of istream / ostream set the badbit?

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I was looking into libstdc++ code and was surprised that it sets the badbit on a stream when an operator>> or operator<< is interupted by a cancellation point of pthread (which, if I understand correctly, is implemented by throwing a special magic exception object).

Apparently, the C++ Standard requires that an exception escaping to the respective I/O function shall set the badbit. But to my understanding, a pthread cancellation isn't needed to be considered an "exception" in the C++ sense.

Does that mean that when calling pthread_cancel'ing a thread that uses cout and friends, one always has to clear the badbit after the thread doing the I/O exited (to be sure just in case the thread caused the badbit to be set)?

asked 57 secs ago

Johannes Schaub - litb

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