ref: a42941eefd1f29dc30efc3ba8d018c7ef4a72d28
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;
}