Is there any definitive way that a threaded app can detect which thread library it is using, the older Linux Threads or the newer Native POSIX Thread Library. I have found a few functions, such as pthread_tryjoin_np(), that exist only in NPTL, but that will prevent a program from linking with the Linux Threads library. -- Jerry Feldman <gaf@blu.org> Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9