Hi, kaffe/kaffevm/systems/unix-pthreads/thread-impl.c reads: #if !defined(__SIGRTMIN) || (__SIGRTMAX - __SIGRTMIN < 7) ... #endif #define SIG_INTERRUPT (__SIGRTMIN+2) What if !defined(__SIGRTMIN)? And that is happening in my case: FreeBSD 5.1-RELEASE on i386.