Hello Bruno, <http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/7552> is an older message and I assume obsolete, now that the specific problem has been fixed in a different manner, but I just stumbled over it again with a solution in mind. Dunno if the general issue is still relevant for gnulib.
* Bruno Haible wrote on Fri, Oct 20, 2006 at 03:52:56PM CEST: > Since gl_FUNC_ALLOCA may invoke AC_LIBOBJ, it must not be AC_REQUIREd - > otherwise it won't work if you use it in two different gnulib libraries from > the same configure.ac file. > > Does anyone know how to write an automatic check for this rule: that > autoconf macros that directly or indirectly invoke AC_LIBOBJ are not > AC_REQUIREd? They may not be directly nor indirectly required, yes? Here's a very nasty hack, messing with deeply internal macros of Autoconf to achieve /almost/ what you want: it complains about macros that call AC_LIBOBJ and that are expanded because of being AC_REQUIRE/m4_require'd by some other macro. So, given AC_DEFUN([FOO], [AC_REQUIRE([BAR])]) AC_DEFUN([BAR], [AC_LIBOBJ([bar])]) it will warn about FOO because that will cause an expansion of BAR due to AC_REQUIRE; but it won't warn about the sequence BAR FOO because when the AC_REQUIRE([BAR]) is encountered, BAR has already been expanded, thus the expansion code isn't gone over again. Tested with CVS Autoconf only. I think it should work with 2.60 and 2.61, but I advise strongly against using this in production code, and promise that it will break eventually. The outer m4_ifdef is merely to disable the code for pre-2.60 Autoconf. It finds about a dozen issues with `gnulib-tool --with-tests --test', so you may want to look at them, see the output at the end of this message. Cheers, Ralf # M4 code to put before or right after AC_INIT: m4_ifdef([_m4_require_call], [m4_rename([_m4_require_call], [_m4_require_call_orig])dnl m4_define([_m4_require_call], [m4_pushdef([AC_LIBOBJ], [m4_warning([AC_LIBOBJ called inside a require chain])dnl m4_expansion_stack_dump()])dnl _m4_require_call_orig($@)[]dnl m4_popdef([AC_LIBOBJ])])dnl ]) configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/getopt.m4:11: gl_GETOPT_SUBSTITUTE is expanded from... glm4/argp.m4:7: gl_ARGP is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/getopt.m4:11: gl_GETOPT_SUBSTITUTE is expanded from... glm4/argp.m4:7: gl_ARGP is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain ../../../autoconf/lib/m4sugar/m4sh.m4:515: AS_IF is expanded from... ../../../autoconf/lib/autoconf/functions.m4:67: AC_CHECK_FUNC is expanded from... ../../../autoconf/lib/autoconf/functions.m4:88: AC_CHECK_FUNCS is expanded from... glm4/getaddrinfo.m4:7: gl_GETADDRINFO is expanded from... glm4/canon-host.m4:13: gl_PREREQ_CANON_HOST is expanded from... glm4/canon-host.m4:7: gl_CANON_HOST is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/save-cwd.m4:7: gl_SAVE_CWD is expanded from... glm4/openat.m4:90: gl_PREREQ_OPENAT is expanded from... glm4/openat.m4:11: gl_FUNC_OPENAT is expanded from... glm4/chdir-long.m4:35: gl_PREREQ_CHDIR_LONG is expanded from... glm4/chdir-long.m4:16: gl_FUNC_CHDIR_LONG is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/openat.m4:69: gl_FUNC_FCHOWNAT is expanded from... glm4/openat.m4:11: gl_FUNC_OPENAT is expanded from... glm4/chdir-long.m4:35: gl_PREREQ_CHDIR_LONG is expanded from... glm4/chdir-long.m4:16: gl_FUNC_CHDIR_LONG is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/fts.m4:17: gl_FUNC_FTS_CORE is expanded from... glm4/fts.m4:7: gl_FUNC_FTS is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain ../../../autoconf/lib/autoconf/functions.m4:831: AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK is expanded from... glm4/lstat.m4:12: gl_FUNC_LSTAT is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain ../../../autoconf/lib/autoconf/functions.m4:932: AC_FUNC_MEMCMP is expanded from... glm4/memcmp.m4:7: gl_FUNC_MEMCMP is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/mktime.m4:15: AC_FUNC_MKTIME is expanded from... glm4/mktime.m4:212: gl_FUNC_MKTIME is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain glm4/strftime.m4:17: gl_FUNC_STRFTIME is expanded from... glm4/strftime.m4:12: gl_FUNC_GNU_STRFTIME is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level configure.ac:921: warning: AC_LIBOBJ called inside a require chain ../../../autoconf/lib/autoconf/functions.m4:1520: AC_FUNC_STRTOD is expanded from... glm4/strtod.m4:7: gl_FUNC_STRTOD is expanded from... configure.ac:47: gl_INIT is expanded from... configure.ac:921: the top level
