Most of those tips are great, but dont use autotools! The points they give for choosing autotools are exactly the same as one would have read maybe a decade ago when people said that CVS was "good enough" and that it "just works." Subversion, git and several others are much better alternatives and where developed because people weren't happy with CVS quirks and crappiness. One example is waf (http://docs.waf.googlecode.com/git/book_16/single.html), arguably just as well documented as autotools but without all the cruft and generated files madness autotools forces you to go through. CMake (http://www.cmake.org/) is another, used by KDE 4. SCons (http://www.scons.org/) another nice build tool. These also have the advantage of working much better on Windows, a platform autotools is completely alien to.
Eh, if it's a C library, use autotools. Really, the original article says it best:
- We are all used to autotools, it works, nobody cares.
...
- And really, anything but autotools is realy an option. Just get over it.
Everything else is an experiment, and it will come back
to you sooner or later. Why? think cross compilation, installation/
uninstallation, build root integration, separate object trees,
standard adherence, tarball handling, make distcheck, testing,
portability between distros, ...
Have you ever tried to port a package that is using autotools to a platform that is not based on GNU/Linux?
Among those of us that have attempted or have done that port, most will probably not look particularly favorably on autotools again.
One of the easiest approaches here involves reverse-engineering the autotools product from a test run performed on a GNU/Linux box, and then translating and building a platform-specific script.
From what I can tell of it, autotools makes substantial use of GNU/Linux features. Which is certainly fine for its intended platform and typical usage, but it's an approach that is Not Fun for porting that code.
Are you kidding? Porting tools to other platforms is the main selling point of autotools. Why do you think it goes to such pains to avoid bash-isms in its output, sticking to raw POSIX shell code, even to the point of avoiding functions and loops? This is specifically to support weird esoteric * -nixes.
Even on Windows, it works fairly well with MingW. Most porting pain comes from bad package management.
Many POSIX-compatible libraries using autotools/libtool can be compiled on OS X without changes, and often MingW too. That isn't true for many other systems.
More importantly, when you do need to make a change, it's a simple edit of shell code and some pretty straight-forward makefile variables. It could just be unfamiliarity, but I've tried customizing the output of CMake for some specific situations and the complexity of the its makefiles is pretty prohibitive. Trying to change the CMake source files for someone unfamiliar with its "language" and variable name conventions is annoying and error-prone.
Autotools will go to great lengths to check if I'm running BSD 4.2, or a specific version of Xenix from 1987, but just you try running it if your "ls" doesn't have a -i flag! Apparently, a filesystem not based around inodes is just inconceivable.
Kidding? No. I'm not. To my point, try porting an autotools package to OpenVMS, for instance. No autotools. Weak bash. No CMake, either. And trying to port autotools itself has been an on-going project; that's been no small effort and attempted by a number of folks, and (so far) no particular success.
gmake scripts are usually fairly portable to OpenVMS, and there is a decent — though not great — ability to invoke bash build scripts directly.
If I had my druthers here, I'd like a build tool that wasn't a layer atop GNU/Linux/Unix — and that's not to imply how autotools works here is at all bad or particularly wrong, it's just an approach that's a bear to port the tools — and have that (portable) build tool then generate the platform-specific build script, build procedure, build-whatever equivalent.
Conceptually: to move the existing builds from a procedural, interpreted approach into a higher-level and object-oriented approach.
> Have you ever tried to port a package that is using autotools to a platform that is not based on GNU/Linux?
I think you mean Unix, not GNU/Linux. Porting from one flavor of Unix to another is the raison d'etre of autoconf. It's really quite valuable when you're the one in charge of babysitting 20-year-old AIX or HPUX boxes.
It's not even meaningful to talk about using the autotools on a non-Unix platform, since autoconf emits shell scripts. It sounds like you've run into problems with automake on a non-Unix platform generating Makefiles with shell code in it?
The thing is, 20 years ago maybe you developed on a Sun box, then the guy down the hall tried to compile it on his HP machine and it crapped itself because of some Sun-related assumption you made in setting things up. Then you mail it to a colleague across the state and he compiles it on OSF/1, hurrah!
But now, people write Linux libraries, tested on a Linux box, for people running Linux, and only compiled on Linux. There may be OS X support. That's it. This is not the 1980s, where 10,000 Unixes bloomed. With 4 Makefiles, you could support Linux, OS X, Windows, and FreeBSD, and thus cover 99% of your audience. I'm sick of watching configure scripts take longer to run than the actual compilation.
Except that before "just supporting Linux (and maybe MacOS)" was the thing to do, it was "just support Sun (and maybe HP-UX)". And before that, it was "just support BSD/Vax (and maybe SVR2)".
So, when you take a broader view than "just support what everyone uses", you're not just helping niche platforms -- you're future-proofing.
Having some experience porting software to embedded architectures, I can tell you that cross compilation can be a hell in autotools projects just as well. In theory it's easy, but all the projects handle it slightly different, or have hacked around autotool limitations in different ways that don't work with cross compilation etc...
And separate object trees is nothing new, all the newer systems don't even mention it as a feature as it's the default (for example, in cmake).
Standard adherence, you could say something for that, though cmake is a standard in a pretty large amount of projects too these days.
Installation/deinstallation. All of the tools support installation and setting install prefix. And nah, half of the time deinstallation doesn't work. I think that's the task of a package manager anyway (or just in case of experimental stuff install into /opt/XXX).
Their arguments are not very convincing IMO. Unlike the rest of the article which is pretty good this is just bikeshedding.
Please do use autotools! You only need two files: configure.ac and Makefile.am, both at the top-level of your project. The autogenerated stuff can be ignored, you don't have to learn M4 to use autoconf. And (if you are a bit careful, but that's not too hard) you'll have many nice features such as out-of-source builds, proper feature checking, amazing portability, 'make distcheck', and acceptable cross-compiling (still hard to get right, but the alternatives tend to be even harder). Don't switch to another build system purely based on the idea that it's "more elegant".
Spend some hours figuring this out... Oh, I need to install an old version of auto*!
How do I get the old one but keep the new one around? Spend another 30 minutes to figure that out.
$ ./autogen.sh
checking for build system type...
^C
No damn, I wanted to generate configure, not run it! How do I clean up the mess it made just now?
$ make clean
$ make distclean
$ ./configure --prefix=$HOME/my_app ...
$ make -j9 install
...
install: no such file or directory blabla.la
WTF!?!?!
Spend an hour or so googling this mess. Ah, it's a parallel-make bug.
$ make install
HOLY SHIT, IT INSTALLED!!!
Let's submit this fix upstream. No problem, use diff.
WTF IS ALL THIS MESS IN THE DIFF I NEVER TOUCHED?!!??!
I know you're going to say I should be using the VCS checkout in the first place, which would hopefully be configured to ignore the autogenerated files. But as a user, or distribution maintainer, most of the time the bug you find is with a specific, packaged version of the software, and it may be quite an effort to figure out how to get the exact same version from the VCS server.
> $ ./autogen.sh
> checking for build system type...
> ^C
>
> No damn, I wanted to generate configure, not run it! How do I clean up the mess it made just now?
I always run "./autogen.sh --help" for exactly that reason; then if I see --help output from configure, I know that autogen.sh "helpfully" ran configure for me.
You can also usually just run "autoreconf -v -f -i" directly, unless the package has done something unusual that it needs to take extra steps in autogen for.
Practically, you need an autogen.sh script too because noone knows the command switches and order you need to call aclocal, autoconf and automake in to generate the configure script and Makefile.in files. That's enough for a minimal project. For something larger with subdirectories for src/ docs/ tests/ etc, you need to use one Makefile.am file in each directory and tie it together with the SUBDIRS variable. When you need to do something slightly out of the extra-ordinary (in autotools' world, "ordinary" means compile c, generate man pages and install) like generating doxygen or javadoc documentation, offering an uninstall option or building binaries that are not supposed to be installed, then you have to learn M4 and it's stupid syntax.
Also, autotools amazing features aren't all that. Builds out of the source dir? Eh.. This is 2012 and it doesn't impress anymore. Both waf and SCons can do it no problem. Autotools-projects, on the other hand, seem to always put the object files and linked library in the source directory. Sometimes the built library is put in a hidden directory for some reason I don't understand. Possibly it has something to do with libtool, another kludge on top of autotools one rather would do without. Since modern build tools does not pollute the source directories you basically get make distcheck for free. Waf has it builtin for example and it can easily be extended to also upload your tarballs to your distribution server, sending annoncement emails and what have you.
I don't want to toot my own horn, but I only check in Makefile.am and configure.ac. Here's a simple example I made a while back: https://github.com/ggreer/fsevents-tools. To build it, just run autogen.sh.
For a "real" project, https://github.com/ggreer/the_silver_searcher, I have the same set-up: Makefile.am and configure.ac with no generated code in the repo. It works fine as long as you have pkg-config, and most people do. It builds and runs on Solaris, OS X, FreeBSD, and any Linux distro you like.
Although I use autotools the "right way", I'm not a fan of it at all. There are multiple levels of generated files. Configure is generated from configure.in which is generated from configure.ac. Makefile is generated from configure and Makefile.in. Makefile.in is generated from Makefile.am. There are other files in the mix as well. Config.h, config.h.in, aclocal.m4, and various symlinks to autotools (compile, depcomp, install-sh, and missing) get generated. It's insane.
There are other problems. Minor versions of autotools can behave completely differently. AM_SILENT_MAKE was removed between automake 1.10 and 1.11. Instead of printing out minimal text during a build, scripts using that macro crash. Another example: 1.9 requires AM_PROG_CC_C_O to compile anything useful but 1.10 doesn't. What's crazy is that 1.9 actually spits out an error message telling you to add AM_PROG_CC_C_O to your configure.ac. It makes no sense.
A system this complicated can't be pruned without breaking backwards compatibility. For autotools, that's not feasible. There are too many projects that would need to be fixed. The next-best solution is to use something else for new projects and let autotools fade gently into history.
I rather dislike autotools (every time I wait for a configure file to make a million compiler tests which could be stored in a global cache, it's wasting my time), but I wish some of the alternative build tools placed a higher priority on being compatible with it rather than inventing their own syntax. If I want to do something like cross compile or even just add custom cflags (ugh, cmake...), I know what configure option will do so, and it's not a particularly bad interface either. From a user's perspective, build systems are usually boring; a consistent user interface makes the world a little simpler.
I know some folks like it in all it's python-y glory, but I found it opaque and horrible. Finding where things are done and how to change its behaviour was surprisingly hard work. Now this may have been at least partly due to the way the project was set up but... well just give me a nice Makefile any day.
As someone who's done a bit of Debian development, I find autotools packages a lot easier to deal with than the alternatives. It might be a bit crufty, but if used properly it works very well.
OK, there are a lot of autoconf scripts that are poorly written, and therefore don't get the benefits. I've never heard of waf. I've never had to fight with scons, but I've never used it for my project.
But, for the love of all that is holy, do not CMake. It works fantastically... until you have to fix something. I tell you this as a distro packager. I've had to fight with build systems. Patching autoconf files, automake files, ant files, are all fairly comfortable for me. I dread the days when I have to figure out an issue with CMake.
Yeah, I concur. I've had miserable experiences with cmake. The autotools have a butt-ugly implementation, but generally work pretty well, and are fairly simple to use, within their domain.
That's the issue, really ... each of these build systems (including the autotools) seems to have a sweet spot where it works pretty well, but can be a misery outside it.
None of them (that I've encountered) are even close to being universally good. Pick your poison wisely...
"The MPL's 'file-level' copyleft is designed to encourage contributors to share modifications they make to your code, while still allowing them to combine your code with code under other licenses (open or proprietary) with minimal restrictions."
Bad idea to choose a GPL-incompatible license for a library, though. If you like the MPL, use it in a dual-license with the GPL or LGPL, like cairo does. Better yet, just use the LGPL or GPL.
With some software (Go code that is always statically linked by the official toolchain comes to mind) you are shooting yourself in the foot with GPL and even LGPL.
It's complicated. To be able to modify, recompile and relink the LGPL part you would have to use the exact version of the go toolchain with which the commercial part was compiled with. Not to mention having to come up with a custom build process that puts the object files in the distributed archive...
CMake is a nightmare on OS X, especially if you have Homebrew installed. If you're wanting to go down this route, gyp is a much better choice, though still rather new.
