I'm now getting: (gdb) i thread 2 Thread 2049 (LWP 301) 0x4005487e in sigsuspend () from /lib/libc.so.6 0x4001f493 in pthread_handle_sigrestart* 1 Thread 1024 (LWP 300) () from /lib/libpthread.so.0 i.e. the order of the fields is reversed. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer