Dear all, I delted the boost folder carelessly,so I had to rebuild boost1_33_1. after i build bjam,I can compile ,run the thread.cpp in /boost_1_33_1/libs/thread/example/ but,when I compile and run the thread_group.cpp,I got these message: (gdb) bt #0 ~function0 (this=0xbffaacd0) at function_template.hpp:313 #1 0x080497c6 in main (argc=1, argv=0xbffaada4) at thread_group.cpp:17 (gdb) step Program received signal SIGSEGV, Segmentation fault. [Switching to Thread -1208067152 (LWP 29013)] 0x08049c57 in boost::detail::function::void_function_invoker0<void (*)(), void>::invoke (function_ptr= {obj_ptr = 0xb7fe53af, const_obj_ptr = 0xb7fe53af, func_ptr = 0xb7fe53af, data = "?}) at function_template.hpp:103 103 BOOST_FUNCTION_RETURN(f(BOOST_FUNCTION_ARGS)); and I got the same message when I use thread_group my system version :Linux version 2.6.9-5.EL ( bhcompile@decompose.build.redhat.com) (gcc version 3.4.3 20041212 (Red Hat 3.4.3-9.EL4)) boost:1.33.1