I'm revisiting an old thread. I'm using autoconf 2.57. http://mail.gnu.org/archive/html/autoconf/2003-06/msg00013.html If I use AC_CHECK_LIB does configure try to *run* the program? What's happening is configure and make run fine, but ldd shows "not found" for libz's runtime linkage. I'm linking with zlib which is installed in /usr/local/lib, but it seems that on this machine (Solaris 2.6) that /usr/local/lib is not part of the default search path. This causes confusion because configure is saying libz is found and then make check fails saying libz is not found. Another thing that is confusing (and I'm not sure if it's related to why configure is not failing the libz check) is that the problem only happens when using a --prefix setting. Without a --prefix the final link link has -R/usr/local/lib added. But if --prefix=/foo is used then that -R setting is *replaced* with -R/foo. I understand that, but I'm wondering if configure should also be prefix aware. So the result is the program only fails when a --prefix is used, which is also confusing for the person trying to install the application. It would be nice if configure would catch this. But I'm not sure if it's because configure is not actually running the test program for zlib, or if configure is using a different -R when linking the test program vs. linking the application. Or maybe it's something completely different. -- Bill Moseley moseley@xxxxxxxx