Hi, this time I compiled with LLVM/GCC 4.2.1. Here are the brief results: dispatch_api: pass dispatch_c99: pass dispatch_cascade: pass dispatch_debug: pass dispatch_priority: fail dispatch_priority2: fail dispatch_starfish: fail, spins forever queue_finalizer: pass dispatch_after: fail, spins forever dispatch_apply: pass dispatch_drift: fail, spins forever dispatch_group: pass dispatch_pingpong: pass dispatch_read: fail, spins forever dispatch_readsync: pass dispatch_sema: pass dispatch_timer_bit31: fail, spins forever dispatch_timer_bit63: fail, spins forever dispatch_plusplus: pass Hopefully, those tasks that don't terminate fail due to the same problem, so I'm going to investigate this issue further. ciao, Mario