Hi, Since ceil() can be inlined when optimization is enabled, I use AC_SEARCH_LIBS([ceil], [m], , [AC_MSG_ERROR([ceil not found])]) AC_SUBST([m_LIBS], [$LIBS]) to link against libm only when necessary (that is, when ceil is not inlined). However, it does not work because GCC says in config.log: conftest.c:76:6: warning: conflicting types for built-in function 'ceil' char ceil (); ~~~~ and inlining is disabled, thus ceil becomes an undefined reference without -lm. However, in the actual code where math.h is #included, the above warning does not happen, ceil is inlined and I unnecessarily link with -lm. How could I overcome this? Please Cc me, I'm not subscribed. -- Thanks, Feri _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx https://lists.gnu.org/mailman/listinfo/autoconf