futex lockup?

Hi,

I wrote a program using pgsql's ESQL/C.  Occasionally it blocks
forever on a system call futex(), and I'm wondering if pgsql's
libraries use this futex call?? (because my code doesn't use it).

Because the problem only occurs occasionally I can't really trace
it while it's running.  But when I discover it's locked up, and
then do a trace, I get the following:

   Process 19893 attached - interrupt to quit
   futex(0x238f20, FUTEX_WAIT, 2, NULL

I'm using psql 8.0.3 on Linux FC4 (kernel 2.6.11-1).

Thankyou,
Rob Newton