:c:func:`PyErr_CheckSignals` has been changed to acquire the global

interpreter lock (GIL) itself, only when necessary (i.e. when it has work to

do). This means that modules that perform lengthy computations with the GIL

released may now call :c:func:`PyErr_CheckSignals` during those computations

without re-acquiring the GIL first. (However, it must be *safe to* acquire

the GIL at each point where :c:func:`PyErr_CheckSignals` is called. Also,

keep in mind that it can run arbitrary Python code before returning to you.)