Hi John I think you're right, and I need to place FPE 'brackets' around my code.
The thing that was confusing me was that python has division by zero exceptions (for which I assumed fenv.h was being used), but when from python I reach down into my SWIG code and do a 1/0, no SIGFPE is thrown. I will experiment with the _controlfp stuff (and linux equivs) and see how it goes. Thanks for your help. Cheers JP On Jan 25, 5:12 pm, John Nagle <[EMAIL PROTECTED]> wrote: > John Pye wrote: > > Hi John, > > > On Jan 25, 3:43 pm, John Nagle <[EMAIL PROTECTED]> wrote: > > >>Python is probably running with floating point exceptions disabled, > >>but you can enable them in your C code, and restoring the floating > >>point mode when you leave, if you want. This is probably > >>only worth doing under a debugger, because otherwise you just end > >>up with an aborted instance of Python. > > > So as far as you know, Python doesn't switch stuff like > > feenableexcept(FE_EXCEPT_ALL)? Does Python use the <signal.h> > > internally, or are all its FPEs detected by explicit checks beforehand? > > I have no idea what state Python leaves the FPU in, but whatever > the state is, you can read it, set your own state, and restore > the previous state before returning to Python. > > The last time I had to do this, I used > > unsigned int oldstate = // make almost all FPU errors fatal > _controlfp ((~_EM_INVALID) & _CW_DEFAULT, _MCW_EM); > ... > _controlfp(oldstate); // restore old state > > on Windows 2000. > > John Nagle -- http://mail.python.org/mailman/listinfo/python-list
