Hello list! We have a problem here with GNU Make's built-in rules that I can't seem to be able to solve. Short version of my question: How can the implicit rule for RCS defined in GNU Make be disabled in a portable way (Automake 1.9.6, Autoconf 2.59)? Using GNU Make syntax, this can be done using
% : RCS/%,v % : %,v but this is not portable to non-GNU Make implementations. Automake throws warnings about these when invoked via `autoreconf -s -i'. Is there a good solution to this problem? Longer version of my question: We are using RCS (Revision Control System) to maintain our sources. In RCS, any file under version control is usually stored in a subdirectory of the file's directory, "RCS/", with all its version history inside and a ",v" tacked to its end (such that for "helloworld.c" there is also a versioned file "RCS/helloworld.c,v"). Files can be checked in and out using commands "ci" and "co", respectively. Unfortunately, for several reasons, we cannot switch to something better than RCS, like Subversion, right now and we are stuck with RCS for at least a while. Our problem is that GNU Make has an implicit rule for this to automatically check out files for which a corresponding ",v" file exists, in the current or RCS directory. Now, in a VPATH build, source files are checked out automatically from $(srcdir)/RCS/ to $(builddir) by that implicit rule, even if they have been checked out before to $(srcdir) by the user. This is really bad because once a file has been checked out to $(builddir) by Make, any changes to the working copy in $(srcdir) go unnoticed since Make sees only the unchanged file in $(builddir). Seems like Automake doesn't know of that annoying implicit rule in GNU Make, which I think is perfectly OK, and hence doesn't introduce dependencies that would trigger a rebuild. Consequently, `make clean' also doesn't remove the checked out files in $(builddir). I tested with a small test case, consisting of minimalistic configure.ac, Makefile.am, and helloworld.c. Then I created a directory "RCS" and checked in helloworld.c using "ci -u helloworld.c" (the -u tells ci to not delete helloworld.c after checking in), and tried desperately... configure.ac: ----- AC_PREREQ(2.59) AC_INIT([RCStest],[1.0],[rhomann.AT.techfak.uni-bielefeld.de],[RCStest]) AM_INIT_AUTOMAKE([-Wall foreign]) AC_CONFIG_SRCDIR([helloworld.c]) AC_CONFIG_HEADER([config.h]) AC_PROG_CC AC_CONFIG_FILES([Makefile]) AC_OUTPUT ----- Makefile.am: ----- bin_PROGRAMS=helloworld helloworld_SOURCES=helloworld.c ----- $ autoreconf -s -i configure.ac: installing `./install-sh' configure.ac: installing `./missing' Makefile.am: installing `./depcomp' All Make implementations I have access to work fine with the Makefiles generated by Automake 1.9.6 and Autoconf 2.59 using the files shown above, only GNU Make exhibits the undesired behavior described before. Appending the two lines % : RCS/%,v % : %,v to Makefile.am results into $ autoreconf -s -i configure.ac: installing `./install-sh' configure.ac: installing `./missing' Makefile.am:3: `%'-style pattern rules are a GNU make extension Makefile.am:4: `%'-style pattern rules are a GNU make extension Makefile.am: installing `./depcomp' So I end up with two warnings and one non-portable Makefile. The Make implementations I have access to are fine with these rules, though, only smake 1.2a23 on Ubuntu 5.10 crashed with a segfault if these rules were present (commenting them out in the generated Makefile made smake pass). Instead, because the GNU Make manual states that `$(CO) $(COFLAGS)' is the command used to check out sources, I also tried the line CO = \# in Automake.am, with minor success. For GNU Make, this resulted in: make all-am make[1]: Entering directory `/amnt/callisto/users/pistaff01/pistaff/rhomann/automake_testing_obj' # ../automake_testing/RCS/helloworld.c,v helloworld.c if gcc -DHAVE_CONFIG_H -I. -I../automake_testing -I. -g -O2 -MT helloworld.o -MD -MP -MF ".deps/helloworld.Tpo" -c -o helloworld.o helloworld.c; \ then mv -f ".deps/helloworld.Tpo" ".deps/helloworld.Po"; else rm -f ".deps/helloworld.Tpo"; exit 1; fi gcc: helloworld.c: No such file or directory gcc: no input files make[1]: *** [helloworld.o] Error 1 make[1]: Leaving directory `/amnt/callisto/users/pistaff01/pistaff/rhomann/automake_testing_obj' make: *** [all] Error 2 Here the CO command has been turned into a comment so nothing got checked out, but the compiler didn't get the full path to the real helloworld.c in $(srcdir), which would have been ../automake_testing/helloworld.c in this case. So, how can I disable the implicit RCS rule in a portable way? Is using an AM_CONDITIONAL in configure.ac to decide between GNU/non-GNU Make the way to go? Or is there a better solution that works with all Make implementations without the help of Autoconf, which is what I would prefer (because we include Automake snippets in Makefile.am files for this in multiple projects and wouldn't need to touch our configure.ac files then)? Sorry for putting short questions into long words... :) bye, Robert -- Windows is not the answer. Windows is the question. The answer is "No".
