ctrl-c and oct files

[John Donoghue]

I have an on file that calls some os code - just as a single example:

#include <octave/oct.h>
#include <unistd.h>

DEFUN_DLD (testctrl, args, nargout, "Test Ctrl-C")
{
  printf("starting sleep\n");

  BEGIN_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;

  sleep(10);

  END_INTERRUPT_IMMEDIATELY_IN_FOREIGN_CODE;

  printf("finished sleep\n");
  return octave_value();
}

Build with mkoctfile, in fedora 26, with octave 4.3.92, hg 
25327:abc5095d58c2


Running it with octave --no-gui, when I run testctrl, and press ctrl-c 
after a second, shouldn't the code break out?

Currently, for me, ctrl-c doesnt appear to do anything - the prints 
execute after the 10 second sleep, rather than breaking out part way 
through the sleep.

octave --gui does the same.