I have simplified my script a bit and here is the output from configure. I believe the critical line is: checking if libtool supports shared libraries... no What I do not understand is why AC_LIBTOOL_WIN32_DLL inside this code has any effect at all: if test 0 = 1; then echo "---- In conditional block 1 ----" AC_LIBTOOL_WIN32_DLL else echo "---- In conditional block 2 ----" fi Apparently, I don't understand how the "if/fi" construct works. I expected it would allow conditionally including AC macros, but that does not seem to be true. :::::::::::::: configure.ac ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: AC_PREREQ(2.52) AC_INIT([testing], [2.0], [testing], [testing]) AC_CONFIG_MACRO_DIR([m4]) AM_INIT_AUTOMAKE AC_CONFIG_SRCDIR([build_config_files.sh]) if test 0 = 1; then echo "---- In conditional block 1 ----" AC_LIBTOOL_WIN32_DLL else echo "---- In conditional block 2 ----" fi AC_PROG_LIBTOOL AC_CONFIG_FILES([Makefile]) AC_OUTPUT :::::::::::::: stdio output of ./configure ::::::::::::::::::::::::::::::::::::::::::::::::::::: checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /bin/mkdir -p checking for gawk... gawk checking whether make sets $(MAKE)... yes ---- In conditional block 2 ---- checking for style of include used by make... GNU checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking dependency style of gcc... none checking for a sed that does not truncate output... /bin/sed checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for fgrep... /bin/grep -F checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B checking the name lister (/usr/bin/nm -B) interface... BSD nm checking whether ln -s works... yes checking the maximum length of command line arguments... 1966080 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking for /usr/bin/ld option to reload object files... -r checking for objdump... objdump checking how to recognize dependent libraries... unknown checking for ar... ar checking for strip... strip checking for ranlib... ranlib checking command to parse /usr/bin/nm -B output from gcc object... ok checking how to run the C preprocessor... gcc -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for dlfcn.h... yes checking for objdir... .libs checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC -DPIC checking if gcc PIC flag -fPIC -DPIC works... yes checking if gcc static flag -static works... no checking if gcc supports -c -o file.o... yes checking if gcc supports -c -o file.o... (cached) yes checking whether the gcc linker (/usr/bin/ld) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... no checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... no checking whether to build shared libraries... no checking whether to build static libraries... yes configure: creating ./config.status config.status: creating Makefile config.status: executing depfiles commands config.status: executing libtool commands ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: I tried zip'ing the generated files and attaching them, but the mailer rejected my message, so I imagine that attachments are not allowed. Doug -----Original Message----- From: Ralf Wildenhues <Ralf.Wildenhues@xxxxxx> To: Dr. Douglas C. MacKenzie <doug@xxxxxxxxxxxxxxxxxxxxxxx> Cc: autoconf@xxxxxxx Subject: Re: Problem with macro inside inactive conditional changing autoconf behavior Date: Sun, 31 Jan 2010 15:54:36 +0100 Hello Douglas, * Dr. Douglas C. MacKenzie wrote on Fri, Jan 29, 2010 at 09:29:31PM CET: > I am having trouble with a configure.ac file after upgrading from > libtool 1.5 to 2.2.6 as part of moving from Fedora 10 to Fedora 12. [...] > > AC_ARG_VAR(COMPILER, "Use COMPILER=MSC to compile for WIN32 using Microsoft C++ compiler.\nUse COMPILER=GCC to comnpile using GNU tools (default).\n") > > if test "x$COMPILER" = "xMSC"; then > > echo "Compiling using Microsoft C++ compiler" > > dnl AC_LIBTOOL_WIN32_DLL > > AC_SUBST(BUILD_WINDOWS, true) > > else > > echo "Compiling using GNU tools" > > AC_SUBST(AM_CXXFLAGS, "-Wall") > > fi [...] > The commands: > autoreconf --force --install > ./configure > ./libtool --features > > generate: > host: x86_64-unknown-linux-gnu > enable shared libraries > enable static libraries > > But, If I change the "dnl AC_LIBTOOL_WIN32_DLL" line to " > AC_LIBTOOL_WIN32_DLL" > > The commands: > autoreconf --force --install > ./configure > ./libtool --features > > Now generate: > host: > disable shared libraries > enable static libraries That's weird. Can you post the configure output in the second case? This is a Libtool issue, not an Autoconf one. That said, it should work to just move the AC_LIBTOOL_WIN32_DLL outside of the if clause, so it is called unconditionally. Another thing you can try is AS_IF([CONDITION], [IF-TRUE], [IF-FALSE]) with Autoconf 2.60 or newer. Another thing to note is that the AC_SUBST macro typically expands to no shell code at all, and it anyway has unconditional effect, so if $foo; then AC_SUBST([bar]) fi will unconditionally substitute @bar@, and likely cause a shell syntax error. Cheers, Ralf _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf