On Sun, Sep 27, 2020 at 10:53 AM Jannick <thirdedition@xxxxxxx> wrote: > > it appears that autoconf's -I flag does not show any effect in simple cases > (namely simple test cases without AC_CONFIG_MACRO_DIRS which implies other > dependencies like AM_INIT_AUTOMAKE). > > The simple example below shows that autoconf passes the -I flag on to > autom4te, but the m4-macro defined in m4/help.m4 is not expanded in > configure. Or is it that hell.m4 is to be explicitly m4_include'd in > configure.ac (which does certainly help here)? If this was correct, what > exactly should one expect autoconf's -I flag to do - in such a simple case > and in general? The effect of `-I m4` on autoconf itself is to let you write `m4_include([hello.m4])` instead of `m4_include([m4/hello.m4])`. If I change your sample configure.ac to read AC_INIT m4_include([hello.m4]) SAY_HELLO AC_OUTPUT then $ autoconf; echo $? /usr/bin/m4:configure.ac:2: cannot open `hello.m4': No such file or directory autom4te: /usr/bin/m4 failed with exit status: 1 1 but $ autoconf -I m4; echo $? 0 $ grep -i hello configure $as_echo Hello! If you want to not have to write the m4_include yourself, you need `aclocal`, which is distributed along with automake, but can be used without automake proper. For instance (same m4/hello.m4) $ cat > configure.ac <<EOF AC_INIT SAY_HELLO AC_OUTPUT EOF $ aclocal -I m4 $ autoconf # -I m4 no longer needed here $ grep -i hello configure $as_echo Hello! $ grep m4_include aclocal.m4 m4_include([m4/hello.m4]) Hope this helps. zw
