waiting on an event blocks all signals

[Diez B. Roggisch]

alan schrieb:
> This ignores CTRL-C on every platform I've tested:
> 
> python -c "import threading; threading.Event().wait()"
> ^C^C^C^C
> 
> It looks to me like all signals are masked before entering wait(). Can
> someone familiar with the internals explain and/or justify this
> behavior? Thanks,

They aren't masked. Read the docs:

# Although Python signal handlers are called asynchronously as far as 
the Python user is concerned, they can only occur between the ``atomic'' 
instructions of the Python interpreter. This means that signals arriving 
during long calculations implemented purely in C (such as regular 
expression matches on large bodies of text) may be delayed for an 
arbitrary amount of time.


(http://docs.python.org/lib/module-signal.html)

Which is what is happening here - wait is implemented in C. So the 
arriving signal is stored flagged in the interpreter so that the next 
bytecode would be the signal-handler set - but the interpreter still 
waits for the blocked call.

Diez