ASS[0] is documented for Linux (and for POSIX) but i'm failing to find any
information on how this applies to Cygwin. I assume, since there are no "real"
signals on Cygwin, that it's not possible for a signal handler to break the
state of some function that happened to be executed when the signal handler was
triggered. But i could be wrong.

[0]: http://man7.org/linux/man-pages/man7/signal-safety.7.html