detecting gdb at runtime?

[Joshua Haberman]

Is there any way to detect GDB at runtime?

I am currently experimenting with different ways to handle errors in a 
C++ library I am writing.  I am using an Assert() macro to verify 
conditions throughout the program, much like C's assert() function.  I 
believe that the best way to respond to a failed assertion is to throw 
an exception because it gives the client application a chance to 
recover as best it can.  However, if the program is running in a 
debugger, throwing an exception is sub-optimal because it cannot give 
you a stack trace.

My goal is to have my Assert() macro SIGTRAP if a debugger is running 
to break into the debugger, otherwise throw an exception.  Is there any 
way to make this happen?

(Please CC me, I am not subscribed).

Josh Haberman