ref: c8a7fdf56b7cd290cc69b7c0763cc0ef91aaee87
dir: /sys/src/cmd/python/Python/sigcheck.c/
/* Sigcheck is similar to intrcheck() but sets an exception when an
   interrupt occurs.  It can't be in the intrcheck.c file since that
   file (and the whole directory it is in) doesn't know about objects
   or exceptions.  It can't be in errors.c because it can be
   overridden (at link time) by a more powerful version implemented in
   signalmodule.c. */
#include "Python.h"
/* ARGSUSED */
int
PyErr_CheckSignals(void)
{
	if (!PyOS_InterruptOccurred())
		return 0;
	PyErr_SetNone(PyExc_KeyboardInterrupt);
	return -1;
}