Need to run as setuid, please read before flaming

["jeff rob" <jeffrobins747 hotmail com>]

I have a program that needs to access the parallel port directly, read data 
from it, display the data and possibly read data again.  The program needs 
to be setuid to access the parallel ports and it needs to be as real-time as 
possible because I am timing the inputs.  I can't use a helper application 
because that's another process running, which further limits the accuracy of 
the timing.  I plan to boot the machine off of a CD with no HD, so I don't 
care about security holes (currently the machines reside in locked cabinets 
and have no network card, so it really doesn't matter what they try to do to 
it).


How does gtkmm/gtk detect that the program is setuid?

I have tried forking ( fork() and vfork() ) the gtkmm part and even 
reassigning the effective UID and GID to their proper values.

What can I do about it?

I can include a link to source code if needed.

Why wasn't this an issue until last week?

I'm running Mandriva 2005 and 2006 and I know the obvious answer to this 
question, but it's really frustrating.


Thank you,
    Jeff Robins

PS:  I have no problem giving credit to the person who provides the answer, 
in the program.