Hi all, I ran into an interesting issue today. Hoping some of you have some insight for me. I needed to use a later addition to the pthreads spec - pthread_mutexaddr_settype (in order to initialize a recursive mutex). To use this function, you need to define __USE_UNIX98 before including pthread.h - at least on my platform (opensuse 11.3 64-bit). I was trying to figure out how to get Autoconf-generated configure scripts to define this macro for me if it was needed. The truth, however, is that if I need UNIX98 functionality, and it's not available on a platform, configure needs to fail (at least in my case). Because the library actually provides the function, but it's not "enabled" in pthread.h, AC_CHECK_FUNCS is succeeding without issue (which I would expect, because of the way it's designed to look for library exports, and not header file entries), but the compiler is complaining that the function is being used without a prototype (which is completely true if __USE_UNIX98 is not defined). What is the correct approach for this situation? Should I simply define __USE_UNIX98 in my source code because I need the associated functionality? Is __USE_UNIX98 a widely used and understood macro? (Google searches didn't really help me understand the proper use of this macro.) TIA, John _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf