Hi! Im want to check for the presence of the GNU Readline library in a configure script. On some systems we need to link to another library in addition to readline for some terminal functions (e.g. tgetent). I tried this: AC_CHECK_LIB(readline, readline,, AC_SEARCH_LIBS(tgetent, ncurses curses tinfo termcap) AC_CHECK_LIB(readline, readline,, AC_MSG_ERROR([readline not available]) ) ) This correctly determines the additional library required if the test program used by configure doesnt compile with -lreadline alone. However the second test for readline does not get invoked because the result of the first test is cached. How can I tell autoconf to forget the result of the first test before doing it the second time? Regards Matthias