[comp.sys.next] NaN and floating point exceptions

windemut@uxh.cso.uiuc.edu (Windemut) (10/10/90)

I have a program where I do a lot of floating point calculations
on the NeXT. Unfortunately there is some bug that leads to illegal
results. From earlier, older machines I am used to a program
aborting when a floating point exception such as a division by
zero or an overflow happens. On the NeXT, all I get is a lot
of NaNs and no indication whatsoever where the illegal operation
might have occurred. GDB seems to be useless. The closest
reference to a possible solution of this problem I found is in
math(3), the manual entry for the libm library. There the 
exception handling is described as being up to the programmer.
Alas, the information is very vague with no hints given
as to actually accomplish that.

How can I gat an oldfashioned, but immensely helpful
"Floating point exception (core dumped)" from my program?

I am quite desperate about this and would appreciate some 
help from somebody who knows.


		Andreas Windemuth
		Theoretical Biophysics
		University of Illinois at Urbana-Champaign