The library libndp.a contains two calls accessable from fortran or C. call brkndp with an integer argument to push or pop something off or onto the ndp stack [only use this for testing], and call chkndp with no arguments to check that the stack is empty - you should be aware that there are plenty of times when there should be something on the NDP stack. I suggest calling it just before your program exits.

...
0.02 NaN
calculation ends

******************************************
NDP reports the following:
  Invalid operation
  Stack underflow (At some point)
******************************************
chkndp - Now coredumping
Aborted (core dumped)
[james@circe chkndp]$

Take me to the files