The program in the attached URL generates four threads
which all immediately exit. When run standalone from the
shell, there are two PIDs devoted to my program, as there
should be (one for the main thread, and one for the thread
manager--the other four exit cleanly). When run from gdb,
however, the same two threads show up, along with four
processes in the zombie state, even though the threads are
all created with the PTHREAD_CREATE_DETACHED flag in their
attributes.

This makes debugging impossible for large programs that
create many short-lived threads, as the process table fills
up quickly.