I have installed app_txfax.c and spandsp-0.0.6. spandsp seemed to go fine. when compiling app_txfax.c I get errors. I am using centos x86_64 5.4. [CC] app_txfax.c -> app_txfax.o In file included from app_txfax.c:28: /home/silentm/MessageNet/digium/asterisk-1.4.30/include/asterisk/lock.h: In function ?ast_mutex_init?: /home/silentm/MessageNet/digium/asterisk-1.4.30/include/asterisk/lock.h:738: warning: implicit declaration of function ?pthread_mutexattr_settype? /home/silentm/MessageNet/digium/asterisk-1.4.30/include/asterisk/lock.h:738: error: ?PTHREAD_MUTEX_RECURSIVE? undeclared (first use in this function) /home/silentm/MessageNet/digium/asterisk-1.4.30/include/asterisk/lock.h:738: error: (Each undeclared identifier is reported only once /home/silentm/MessageNet/digium/asterisk-1.4.30/include/asterisk/lock.h:738: error: for each function it appears in.) the PTHREAD_MUTEX_RECURSIVE is in /usr/include/pthread.h and around ifdefs for __USE_UNIX98 What do I do about this? Jerry