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//usr/share/doc/autoconf/TODO
-*- 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. ------------------------------------------------------------------------------ * Soon ** AC_CHECK_HEADERS and the like, don't have a consistent way to handle multi-line arguments. Fix, test, and document. ** --target & AC_ARG_PROGRAM Shouldn't *any* `program' be installed as `$target_alias-program' even if AC_ARG_PROGRAM is not called? That would be much more predictable. Ian? ** AC_CHECK_TOOL... Write a test that checks that it honors the values set by the user. ** autom4te and warnings. Decide what must be done. ** AC_DEFINE(func, rpl_func) This scheme causes problems: if for instance, #define malloc rpl_malloc, then the rest of configure will use an undefined malloc. Hence some tests fail. Up to now we simply #undef these functions where we had a problem (cf. AC_FUNC_MKTIME and AC_FUNC_MMAP for instance). This is _bad_. Maybe the #define func rpl_malloc should be performed in another file than confdefs.h, say confh.h, which is used for config.h generation, but not used in configure's own tests. ** AC_PROG_CC Currently it tries to put the C compiler in ANSI C mode by default. We should change this spec so that AC_PROG_CC tries to change the compiler to be the "nicest" mode, i.e. support for the latest standard features (currently ISO C99) plus support for all vendor extensions, even if they are slightly incompatible with C99. The basic idea here is that AC_PROG_CC should disable pedanticisms and should enable extensions. Have a way to specify different default flags to try; see this thread for more information: <http://lists.gnu.org/archive/html/bug-autoconf/2008-08/msg00009.html>. * Later ** config.site This guy is really a problem. It's contents should be read before handling the options, so that the latter properly override the latter, but most people would want a means to have a config.site that depends on $prefix for instance. Some other would like config.site to be looked for in the current directory. Harlan: I'll go further. I'd like to see several layers of config.site available. I'm starting to use "modules" at more places to handle software installation, and it would be helpful to set general things like: prefix=/opt/pkg/@PACKAGE@/@VERSION@ once at a global level, and then, for example, have things like: --with-etcdir=$prefix/etc stuffed "above" the various versions of SSH so I wouldn't have to hunt for these things every time it was time to recompile a new version of a previously installed package. Something like: src/config.site Global stuff ... src/ssh/config.site package-specific stuff src/ssh/ssh-1.2.27/ the actual source code I'd like to see automake/autoconf better support packaging tools (like modules, the *BSD ports/ stuff, and others would like hooks for RPMs). ** Languages Integrate other Fortrans etc. ** AC_CHECK_FUNCS and AC_TRY_LINK_FUNC I have still not understood what's the difference between the two which requires to have two different sources: AC_LANG_CALL and AC_LANG_FUNC_LINK_TRY (which names seem to be inappropriate). Wouldn't one be enough? ** Libtool Define once for all the hooks they need, any redefinition of AC_PROG_CC etc. is way too dangerous and too limiting. The GCC team certainly has requirements too. ** AC_SEARCH_LIBS From: Tom Tromey <tromey@cygnus.com> Subject: AC_SEARCH_LIBS I think AC_SEARCH_LIBS has an unfortunate interface. ACTION-IF-FOUND is run in addition to the default action. Most autoconf macros don't work this way. This is confusing. In my case I can't use this macro because it always appends to LIBS. I don't want that. Instead I want to use ACTION-IF-FOUND to set my own macro. Also there is no documentation on the format of library names expected by the macro. Even a reference to some other function (e.g., "the library name can have the same forms as with AC_HAVE_LIBRARY" (if that is true, which I haven't looked up) would be fine. ** Revamp the language support We should probably have a language for C89, and C99. We must give the means to the users to specify some needs over the compilers, and actually look for a good compiler, instead of stopping at the first compiler we find. In fact, the AC_CHECK_PROG macro and variations have proved their limitation: we really need something more powerful and simpler too. We must take into account the specific problems of the GCC team. We must extend AC_CHECK_FUNCS in order to use the headers instead of fake declarations as we currently do. Default headers could be triggered on when C99, but not with the other languages? At the end, we should have a simple macro, such as AC_LANG_COMPILER for instance, which is built over simpler macros. Each language support should come with these simpler macros, but each language should follow the same process. We also need to check the srcext which are supported by the compiler. In fact, this macro is also probably the right place to check for objext and exeext. ** AC_PROG_CC_STDC Should be: AC_PROG_CC_ISO? Or even more specific for the ISO version? Should include more tests (e.g., AC_C_CONST etc.)? See Peter for very useful comments on the technology. Should we make this a new language? AC_LANG(ISO C). It would be great to introduce AC_LANG_COMPILER in this release too. ** autoupdate We should probably install the files which do not depend upon the user, just the Autoconf library files. But conversely autoupdate must be opened to user macros, i.e., for instance libtool itself must be able to say that AM_PROG_LIBTOOL is now AC_PROG_LIBTOOL, and have autoupdate do its job on old configure.ac. * Even later ** Pentateuch Heck, there is nothing after `Deuteronomy'! We're stuck, but we _must_ update the `history' section. Can't go to `New testament', we might hurt feelings? In addition, it means that the Messiah has come, which might be slightly presumptuous :). Still, someone fluent in English should write it. ** AC_PATH_X Hi Robert, > Hi, autoconf people. While packaging plotutils-2.2 (just released), > I noticed what looks like a small error in the autoconf-2.13 texinfo > documentation, the entry for AC_PATH_XTRA, in particular. > The documentation says that AC_PATH_XTRA > ... adds the C compiler flags that X needs to output variable > `X_CFLAGS', and the X linker flags to `X_LIBS'. If X is not > available, adds `-DX_DISPLAY_MISSING' to `X_CFLAGS'. > It doesn't seem to add -DX_DISPLAY_MISSING to X_CFLAGS. X_DISPLAY_MISSING > ends up defined in config.h, instead. That's only because you're no doubt using AC_CONFIG_HEADER(..) to send your defines to a config.h-style file. If you were to not use AC_CONFIG_HEADER and X was not available, then you would see -DX_DISPLAY_MISSING being added to @DEFS@ as your output files were being generated. But you are right--the documentation is not clear about this. I'll change it. > In fact it looks to me as if right now, X_CFLAGS is used only for > specifying directories where X include files are stored, via the `-I' option. > Maybe it should really be called X_CPPFLAGS? Well, perhaps. If you feel strongly about this, feel free to submit a change-request. There is a hyperlink to the bug tracking database from http://sourceware.cygnus.com/autoconf/. With the way it reads in the manual right now, it's designed to allow the user to set additional flags in the environment prior to running configure--and these don't need to be limited to just -I flags. Nevertheless, I can see a few clean ways to improve this. ** AC_SYS_INTERPRETER Defines $interpval. This is not a standard name. Do we want to keep this? Clarify our policy on those names. ** Allow --recursive to config.status So that --recheck does not pass --no-recursive to configure. * autoconf.texi Move the specific macro documentation blocks into the source files, and use a doc-block extraction/merge technique to get documentation into texi-file. This should help avoid bit-rot in the doc, and make the doc easier to update when people add/change macros. The name "autodoc" is probably already taken so we probably need another one. ------------------------------------------------------------------------------ * m4 ** I18n The error messages for indir and dumpdef are uselessly different. Fix this for translators. ** Tracing `builtin' F**k! --trace FOO does not catch indir([FOO], $@)! Fixed in M4 1.6, but we can't rely on it yet. ** m4 loops As of 2.63, m4_for has a fixed iteration count for speed in the common usage case. But it used to allow the user to alter iteration count by reassigning the iterator, allowing a break-like functionality (or even infloops). Does this need a new (but maybe slower) macro? Should we also provide something like m4_while([TEST], [EXPR])? Maybe an m4_break() that works inside a looping construct? http://lists.gnu.org/archive/html/autoconf-patches/2008-08/msg00121.html * Autoconf 3 ** 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. ** 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. ------------------------------------------------------------------------------ * 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 ------------------------------------------------------------------------------ * Select the right CONFIG_SHELL automatically (for Ultrix, Lynx especially.) ------------------------------------------------------------------------------ * Doc: Centralize information on POSIX, MS-DOS, cross-compiling, and other important topics. ------------------------------------------------------------------------------ * Mike Haertel's suggestions: ** 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. ------------------------------------------------------------------------------ * Look at user contributed macros: IEEE double precision math more ------------------------------------------------------------------------------ * Provide a way to create a config.h *and* set the DEFS variable from within the same configure script. ------------------------------------------------------------------------------ In config.status comment, put the host/target/build types, if used. ------------------------------------------------------------------------------ It would be nice if I could (in the Makefile.in files) set the relative name of 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" <rsw@eng.umd.edu> ------------------------------------------------------------------------------ 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_ <eichin@cygnus.com> ------------------------------------------------------------------------------ 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 appropriate checks, the existence of the files, 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 names 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$target"; then AC_CHECK_PROGS(AR_FOR_TARGET, [$target-ar, $prefix/$target/bin/ar], $target-ar) AC_CHECK_PROGS(RANLIB_FOR_TARGET, $target-ranlib, $target-ranlib) [$target-ranlib, $prefix/$target/bin/ranlib], $target-ranlib) AC_CHECK_PROGS(GCC_FOR_TARGET, $target-gcc, $target-gcc) [$target-gcc, $prefix/$target/bin/gcc], $target-gcc) fi From: nennker@cs.tu-berlin.DE (Axel Nennker) (also look in the autoconf mailing list archives for the proposed CHECK_TARGET_TOOL macro from Natanael Nerode, a gcc configury guru). ------------------------------------------------------------------------------ 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 <rsalz@osf.org> ------------------------------------------------------------------------------ Timezone calculations checks. ------------------------------------------------------------------------------ Support different default file system layouts, e.g. SVR4, Linux. Of course, this can be done locally with config.site. ------------------------------------------------------------------------------ I wonder if it is possible to get the name of 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 <eserte@cabulja.herceg.de> ------------------------------------------------------------------------------ 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 <rboykin@cscsun3.larc.nasa.gov> 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 suppresses the "checking for...result" messages, not the "creating FOO" messages. I think the default should be to suppress both. From: Richard Stallman <rms@gnu.ai.mit.edu> 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 <roland@gnu.ai.mit.edu> ------------------------------------------------------------------------------ Another thing I wish for is a macro which figures out which libraries are needed for BSD-style sockets. AC_PATH_X already detects this correctly...so it's just a matter of separating out the socket-related code. From: "Joel N. Weber II" <nemo@koa.iolani.honolulu.hi.us> ------------------------------------------------------------------------------ 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. ------------------------------------------------------------------------------ Copyright (C) 1994-1996, 1999-2002, 2007-2012 Free Software Foundation, Inc. Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without warranty of any kind.
