-*- outline -*- Things it might be nice to do someday. I haven't evaluated all of these suggestions... their presence here doesn't imply my endorsement. -djm & his successors. ------------------------------------------------------------------------------ * Required for 2.15 These are things mandatory to fulfill before releasing 2.15. There are also suggestions we should either satisfy right now (they're easy), or remove (obsoleted since then). ** AU_ Document. ** m4 The error messages for indir and dumpdef are uselessly different. Fix this for translators. ** config.log Instead of >config.log, how about >>config.log? This would avoid having to tell users to rm config.cache before sending us config.log. ** AC_LANG I don't understand why we have this weird system of AC_SAVE and RESTORE, why not push/pop etc? ** AC_LANG I don't understand why we have this weird system of AC_SAVE and RESTORE, why not push/pop etc? ** AC_PROVIDE I think it is the epilogue that should provide, not the prologue. Not clear: there are risks of circular dependencies :(. In fact the relationship AC_BEFORE should be given outside the macro themselves. ** AC_SYS_INTERPRETER Defines $interpval. This is not a standard name. Do we want to keep this? ** Automake The test for a recent missing doesn't hide the error messages from the old missing. ** Document AH_DEFUN ** automake The section for old macros is not completely up to date. For instance, there is still AM_PROG_LIBTOOL. Anyawy, since autoupdate takes care of them, it is no longer the role of Automake to handle this. Most should be removed. ** AC_INCLUDE m4_include_unique should probably check only for the base name, to warn includes of foo/bar.m4 and baz/bar.m4. AC_INCLUDES could admit $2 to specify the directory? Or do we want another macro to define the m4/ dir, a la AC_CONFIG_AUXDIR. ** Doc: autoconf Document --install. Should --install `fix' configure.in for the user? ** AC_ARG_VAR If should check that none of the envvar it is in charge of, has changed. The configure.in writer may supply what to do (FATAL, WARN etc.). See VALIDATE CACHE TUPLE. Write the documentation of AC_ARG_VAR. Where should it go? ** autoconf.texi: config.status in node names. The info mode of Emacs seems to have problems with this. The info reader catches this properly, so we should report to the X?Emacs teams. Bug triggered by looking for `CONFIG_FILES' in the index. ** AC_CONFIG_COMMANDS_PRE, AC_CONFIG_COMMANDS_POST. We still have to discuss a few issues: should the pre-commands be run before the cache is created? Document, see above. ** Allow --recursive to config.status So that --recheck does not pass --no-recursive to configure. ** Move AM_PROG_CC_STDC into Autoconf. Autoconf should provide the means to determine the ANSIsm of the compiler, not Automake. I've done it, but this is the last opportunity to change this macro name: AC_PROG_CC_ISO? Or even more specific for the ISO version? ** Document GNATS? ** We should remove obsolete things. Both in the doc and the code. Looking for the keyword `obsolete' proves to be useful. Hm, RMS is not happy with this, and I fear we can't go against his opinion on this. Now that we have AU_, maybe we should restore the macro that are DEFUNCT? ** Clarify exactly our position wrt `#define' templates. The fact that there are `#define' templates forbids many useful optimizations. In fact, who really uses #define template in config.h.in? ** Mention automake, libtool, etc. in the Autoconf manual. ** More C compilers (How come this has never been handled? --akim) Question: at least one common UNIX variant has a "cc" that is old K&R and "c89" for ANSI C. Is there any reason why AC_PROG_CC couldn't check for c89 before cc if it can't find gcc? hpa@yggdrasil.com (H. Peter Anvin) ** @magic@ expanded in all the AC_SUBST (I think this one is obsoleted with the existence of Automake. Remove this wish? --akim) Perhaps Autoconf could have a single @magic@ frob that gets replaced with assignments for all the *dir variables? There is quite a plethora for each Makefile.in to have foodir = @foodir@. From: Roland McGrath ------------------------------------------------------------------------------ * Autoconf 3 ** Find a solution for LIBOBJS Currently Automake has no clean way to get the list of files that are required for the distribution. One aspect of this is LIBOBJS. But we can imagine going further and provide a mean for macro authors to specify various files they need to distribute (headers, files to compile and others). ** Improve autoupdate Autoupdate is precious: it is thanks to it that we are quite free on breaking compatibility. In particular, it is not normal to code twice the mapping from old macro to new macro. We could have a AU_ series which is used both for the AC_OBSOLETE messages, and for autoupdate. ** Split all those &#@! files. acgeneral and acspecific is a bad design. The split should be done according to the families. For instance AC_CHECK_FUNCS, AC_CHECK_FUNC, AC_FUNC_FNMATCH etc. *and* AH_CHECK_FUNCS, AU_* should be in, acfunc.m4. I suppose there should be small exceptions, e.g., the family AC_REPLACE_FUNCS should still be in acfunc.m4. ** Cache name spaces. Cf the discussion with Kaveh. One would like to AC_CHECK_FUNCS(bar) # Do something that changes the environment AC_CACHE_PUSH(foo) AC_CHECK_FUNCS(bar) AC_CACHE_POP in order not to erase the results of a check with another. ** Cache var names should depend upon the current language. ** Use m4 lists? I think one sad decision in Autoconf was to use white space separated lists for some arguments. For instance AC_CHECK_FUNCS(foo bar). I tend to think that, even if it is not as nice, we should use m4 lists, i.e., AC_CHECK_FUNCS((foo, bar)) in this case. This would ease specializing loops, and more importantly, make them much more robust. A typical example of things that can be performed if we use m4 lists instead of white space separated lists is the case of things that have a space in their names, eg, structures. With the current scheme it would be extremely difficult to loop over AC_CHECK_STRUCTS(struct foo struct bar), while it natural and well defined for m4 lists: AC_CHECK_STRUCTS((struct foo, struct bar)). I know that makes a huge difference in syntax, but a major release should be ready to settle a new world. We *can* provide helping tools for the transition. Considering the benefits, I really think it is worth thinking. --akim ** Forbid shell variables as main arguments The fact that we have to support shell variables as main argument forbids many interesting constructions (specialization are not always possible, equally for AC_REQUIRE'ing macros *with their arguments*). Any loop should be handled by m4 itself, and nothing should be hidden to it. As a consequence, shell variables on the main arguments become useless (the main reason we support shell variables is to allow the loop versions of single argument macros, eg, to go from AC_CHECK_FUNC to AC_CHECK_FUNCS). --akim ** Use the @SUBST@ technology also for headers instead of #undef. This requires that acconfig.h becomes completely obsolete: autoheader should generate all the templates. ** Specializing loops. For instance, make AC_CHECK_FUNC[S] automatically use any particular macros for the listed functions. This requires to obsolete the feature `break' in ACTION-IF, since all the loops are to be handled by m4, not sh. ** Merge the two lex macros, AC_PROG_LEX and AC_DECL_YYTEXT? Add give a mean to *require* Flex instead of Lex. Or at least explain how to do that. ** Faces of a test Each macro can potentially come with several faces: of course the configure snippet (AC_foo), a config.h snippet (AH_foo), a system.h snippet (AS_foo), documentation (AD_foo) and, why not, the some C code for instance to replace a function. The motivation for the `faces' is to encapsulate. It is abnormal that once one has a configure macro, then she has to read somewhere to find the piece of system.h to use etc. The macros should come in a self-contained way, or, said it another way, PnP. A major issue is that of specialization. AC_CHECK_HEADER (or another name) for instance, will have as an effect, via system.h to include the header. But if the test for the header is specific, the generic AS_CHECK_HEADER will still be used. Conversely, some headers may not require a specific AC_ tests, but a specialized AS_ macro. ------------------------------------------------------------------------------ * Matthew D. Langston's suggestions: ** Change all of Autoconf's macros that print a help string via "configure --help" to use new AC_HELP_STRING macro. ------------------------------------------------------------------------------ * Make AC_CHECK_LIB check whether the function is already available before checking for the library. This might involve adding another kind of cache variable to indicate whether a given function needs a given library. The current ac_cv_func_ variables are intended to indicate whether the function is in the default libraries, but actually also take into account whatever value LIBS had when they were checked for. Isn't this the issue of AC_SEARCH_LIB? --akim How come the list of libraries to browse not an additional parameter of AC_CHECK_FUNC, exactly like for the headers? --akim ------------------------------------------------------------------------------ * Add AC_PROG_CC_POSIX to replace the current ad-hoc macros for AIX, Minix, ISC, etc. ------------------------------------------------------------------------------ * Support creating both config.h and DEFS in the same configure. ------------------------------------------------------------------------------ * Select the right CONFIG_SHELL automatically (for Ultrix, Lynx especially.) ------------------------------------------------------------------------------ * Doc: Add a concept index. ------------------------------------------------------------------------------ * Doc: Centralize information on POSIX, MS-DOS, cross-compiling, and other important topics. ------------------------------------------------------------------------------ * Split up AC_SUBST substitutions using a loop to accommodate shells with severely limited here document sizes, if it turns out to be a problem. I'm not sure whether the limit is on lines or bytes; if bytes, it will be less of a problem than it was with the long lines used for creating a header file. ------------------------------------------------------------------------------ * Allow [ and ] in AC_DEFINE args. ------------------------------------------------------------------------------ * Mike Haertel's suggestions: ** Provide header files containing decls for alloca, strings, etc. ** Cross compiling: *** Error messages include instructions for overriding defaults using config.site. *** Distribute a config.site corresponding to a hypothetical bare POSIX system with c89. ** Site defaults: *** Convention for consistency checking of env vars and options in config.site so config.site can print obnoxious messages if it doesn't like options or env vars that users use. ------------------------------------------------------------------------------ * autoscan: Tell the files that caused inclusion of each macro, in a dnl comment. (Seems to be hard.) ------------------------------------------------------------------------------ * Look at user contributed macros: IEEE double precision math more ------------------------------------------------------------------------------ For AC_TYPE_SIGNAL signal handlers, provide a way for code to know whether to do "return 0" or "return" (int vs void) to avoid compiler warnings. (Roland McGrath) ------------------------------------------------------------------------------ In config.status comment, put the host/target/build types, if used. ------------------------------------------------------------------------------ The default of unlimited permission is fine, but there should be some easy way for configure to have copyright terms passed through from configure.in. Maybe AC_LICENSE([...]). From: roland@gnu.ai.mit.edu (Roland McGrath) ------------------------------------------------------------------------------ AC_MSG_CHECKING([checking for ANSI #stringize]) AC_REVISION([ #(@) revision 2.1 ]) causes bogus code to be generated for whatever immediately follows. The problem goes away if the '#' is removed. Probably the macros are not disabling the m4 "comment" feature when processing user-supplied strings. -Jim Avera jima@netcom.com ------------------------------------------------------------------------------ on hal.gnu.ai.mit.edu, configure is getting the wrong answer for AC_CHECK_FUNCS(select). The problem here is that there's severe name space pollution: when conftest.c includes to pick up any __stub macro definitions, it's getting a prototype declaration for select(), which collides with the dummy declaration in conftest.c. (The chain of includes is conftest.c -> -> -> -> -> .) #define $ac_func __dummy_$ac_func #include #undef $ac_func From: kwzh@gnu.ai.mit.edu (Karl Heuer) The test for the isascii function was failing because that function is also a macro. He proposed that the test file look like this: /* Remove any macro definition. */ #undef isascii /* Override any gcc2 internal prototype to avoid an error. */ char isascii(); isascii(); Andreas Schwab ------------------------------------------------------------------------------ put all the config.* stuff somewhere like config/? All these extraneous files sure clutter up a top level directory. From: "Randall S. Winchester" ------------------------------------------------------------------------------ It would be nice if I could (in the Makefile.in files) set the path to config.h. You have config.h ../config.h ../../config.h's all over the place, in the findutils-4.1 directory. From: "Randall S. Winchester" ------------------------------------------------------------------------------ In libc and make in aclocal.m4 I have AC_CHECK_SYMBOL, which checks for sys_siglist et al. Using AC_CHECK_FUNC doesn't work on some system that winds up caring that you reference it as a function and it is really a variable. My version always declares the symbol as a char *[]; if that ends up a bad idea, we can have it take an arg with the C decl, but that is a bit verbose to write if it's actually superfluous. From Roland McGrath. [I'd call it AC_CHECK_VAR, I think. -djm] ------------------------------------------------------------------------------ In a future version (after 2.2), make AC_PROG_{CC,RANLIB,anything else} use AC_CHECK_TOOL. From Roland McGrath. ------------------------------------------------------------------------------ ls -lt configure configure.in | sort doesn't work right if configure.in is from a symlink farm, where the symlink has either a timestamp of its own, or under BSD 4.4, it has the timestamp of the current directory, neither of which helps. Changing it to ls -Llt configure configure.in | sort works for me, though I don't know how portable that is _Mark_ ------------------------------------------------------------------------------ Here is the thing I would like the most; AC_PKG_WITH(PACKAGE, HELP_STRING, PACKAGE-ROOT, PACKAGE-LIBS, PACKAGE-DEFS, PACKAGE-CCPFLAGS) like AC_PKG_WITH(kerberos,,/usr/local/athena,-lkrb -ldes,[KERBEROS KRB4 CRYPT],include) AC_PKG_WITH(hesiod, [if hesiod is not in kerberos-root add --with-hesiod-root=somewhere] ,,-lhesiod,HESIOD,,) AC_PKG_WITH(glue,,,-lglue,GLUE,,) AC_PKG_WITH(bind,,/usr/local/bind, [lib/resolv.a lib/lib44bsd.a], ,include) After the apropriate checks, the existance of the paths, and libs and such LIBS=$LIBS $PKG-LIBS DEFS=$DEFS $PKG-DEFS CPPFLAGS=$PKG-CPPFLAGS $CPPFLAGS $PKG-ROOT=$PKG-ROOT The cppflags should reverse the order so that you can have; -I/usr/local/bind/include -I/usr/local/athena/include and -L/usr/local/athena/lib -lkrb -ldes /usr/local/bind/lib/libresolv.a as order matters. also an AC_PKG_CHK_HEADER and an AC_PKG_CHK_FUNCTION so one can give alternate paths to check for stuff ($PKG-ROOT/lib for example) From: Randall Winchester ------------------------------------------------------------------------------ AC_C_CROSS assumes that configure was called like 'CC=target-gcc; ./configure'. I want to write a package that has target dependent libraries and host dependent tools. So I don't like to lose the distinction between CC and [G]CC_FOR_TARGET. AC_C_CROSS should check for equality of target and host. It would be great if GCC_FOR_TARGET AR_FOR_TARGET RANLIB_FOR_TARGET would be set automatically if host != target. AC_LANG_CROSS_C would be nice too, to check header files etc. with GCC_FOR_TARGET instead of CC Here is one simple test if test "x$host" != "x$target"; then AC_PROGRAMS_CHECK(AR_FOR_TARGET, $target-ar, $target-ar, ar) AC_PROGRAMS_CHECK(RANLIB_FOR_TARGET, $target-ranlib, $target-ranlib, ranlib) AC_PROGRAMS_CHECK(GCC_FOR_TARGET, $target-gcc, $target-gcc, gcc) fi This could be improved to also look for gcc in PATH, but require the prefix to contain the target e.g.: target=m68k-coff -->GCC_FOR_TARGET = /usr/gnu/m68k-coff/bin/gcc From: nennker@cs.tu-berlin.DE (Axel Nennker) ------------------------------------------------------------------------------ The problem occurs with the following libc functions in SunOS 5.4: fnmatch glob globfree regcomp regexec regerror regfree wordexp wordfree It also occurs with a bunch more libposix4 functions that most people probably aren't worried about yet, e.g. shm_open. All these functions fail with errno set to ENOSYS (89) ``Operation not applicable''. Perhaps Autoconf should have a specific macro for fnmatch, another for glob+globfree, another for regcomp+regexec+regerror+regfree, and another for wordexp+wordfree. This wouldn't solve the problem in general, but it should work for Solaris 2.4. Or Autoconf could limit itself to fnmatch and regcomp, the only two functions that I know have been a problem so far. From Paul Eggert. ------------------------------------------------------------------------------ Make easy macros for checking for X functions and libraries, such as Motif. ------------------------------------------------------------------------------ There are basically three ways to lock files lockf, fnctl, flock I'd be interested in adding a macro to pick the "right one" if you're interested. From: Rich Salz ------------------------------------------------------------------------------ Timezone calculations checks. ------------------------------------------------------------------------------ Support different default filesystem layouts, e.g. SVR4, Linux. Of course, this can be done locally with config.site. ------------------------------------------------------------------------------ I wonder if it is possible to get the path for X11's app-defaults directory by autoconf. Moreover, I'd like to have a general way of accessing imake variables by autoconf, something like AC_DEFINE(WINE_APP_DEFAULTS, AC_IMAKE_VAR(XAPPLOADDIR)) Slaven Rezic ------------------------------------------------------------------------------ Cache consistency checking: ignore cache if environment (CC or PATH) differs. From Mike Haertel So we need a general mechanism for storing variables' values in the cache, and checking if they are the same after reading the cache. Then we can add to the list of variables as we come across the need. So far we want LD_LIBRARY_PATH and the internal variables for some of (all?) the args. From: roland@gnu.ai.mit.edu (Roland McGrath) Hmm. That list might include LD_LIBRARY_PATH, LD_RUN_PATH (for solaris), and PATH. I can't think of any others so far. From: friedman@splode.com (Noah Friedman) ------------------------------------------------------------------------------ So how about an option to configure --reset-cache, that says to ignore all existing cached values for tests that configure runs, and then update the cache normally. This should be utterly trivial to do in AC_CACHE_VAL; check the flag variable and always compute the value if it's set. ------------------------------------------------------------------------------ Every user running X11 usually has a directory like *X11* in his PATH variable. By replacing bin by include, you can find good places to look for the include files or libraries. From: rcb5@win.tue.nl (Richard Verhoeven) ------------------------------------------------------------------------------ In most cases, when autoscan suggests something, using the search or index command into the Info reader for autoconf manual quickly explains me what the test is about. However, for header files and functions, the search might fail, because the test is not of the specific kind. The Autoconf manual should reflect somewhere all header files or functions (non-specific features, generally) triggering autoscan to generate tests, and tell in a few words what is the problem, and the suggested approach for a solution; that is, how one should use the result of testing the feature. From: pinard@iro.umontreal.ca ------------------------------------------------------------------------------ It would be nice if the configure script would handle an option such as --x-libraries="/usr/openwin/lib /usr/dt/lib". Rick Boykin Under Solaris 2.4, the regular X includes and libs and the Motif includes and libs are in different places. The Emacs configure script actually allows dir1:dir2:dir3 -- if test "${x_libraries}" != NONE && test -n "${x_libraries}"; then LD_SWITCH_X_SITE=-L`echo ${x_libraries} | sed -e "s/:/ -L/g"` LD_SWITCH_X_SITE_AUX=-R`echo ${x_libraries} | sed -e "s/:/ -R/g"` fi if test "${x_includes}" != NONE && test -n "${x_includes}"; then C_SWITCH_X_SITE=-I`echo ${x_includes} | sed -e "s/:/ -I/g"` fi ------------------------------------------------------------------------------ What messages should be produced by default, if any? Probably only the few most important ones, like which configuration name was used, whether X or Xt are in use, etc. The specific decisions, and progress messages, should be recorded on the terminal only if --verbose is used. --silent just supresses the "checking for...result" messages, not the "creating FOO" messages. I think the default should be to suppress both. From: Richard Stallman There is no distinction now between important decisions (we have X) vs minor decisions (we have lstat). However, there are probably only a few things you deem important enough to announce and only those few things will need to be changed. Perhaps config.status could be written with comments saying what was decided. From: Roland McGrath ------------------------------------------------------------------------------ Another thing I wish for is a macro which figures out which libraries are needed for BSD-sytle sockets. AC_PATH_X already detects this correctly...so it's just a matter of seperating out the socket-related code. From: "Joel N. Weber II" ------------------------------------------------------------------------------ in order to use the AC_CANONICAL_SYSTEM macro, I have to have install-sh somewhere nearby --- why is this? I have no real reason to distribute install-sh, other than that its absence breaks this code. Shouldn't the above loop be looking for config.sub and config.guess? From: jimb@totoro.bio.indiana.edu (Jim Blandy) adding AC_CANONICAL_HOST to my configure.in script caused all sorts of odd/unexplained errors. Obviously, I had to go get copies of config.guess, config.sub and install-sh from the autoconf distribution, but the error messages and autoconf docs didn't explain that very well. From: bostic@bsdi.com (Keith Bostic) ------------------------------------------------------------------------------ Perhaps also have AC_TRY_COMPILER try to link an invalid program, and die if the compiler seemed to succeed--in which case it's not usable with autoconf scripts. ------------------------------------------------------------------------------ autoreconf doesn't support having (in the same tree) both directories that are parts of a larger package (sharing aclocal.m4 and acconfig.h), and directories that are independent packages (each with their own ac*). It assumes that they are all part of the same package, if you use --localdir, or that each directory is a separate package, if you don't use it. autoreconf should automatically figure out which ac* files to use--the closest ones up the tree from each directory, probably, unless overridden by --localdir. Also, autoreconf recurses on all subdirectories containing a configure.in, not just those given by an AC_CONFIG_SUBDIRS directive. This may not be a problem in practice. ------------------------------------------------------------------------------