Confused about configure script and Makefile.in
Solution 1
In order to really understand the autotools utilities you have to remember where they come from: they come from an open source world where there are (a) developers who are working from a source code repository (CVS, Git, etc.) and creating a tar file or similar containing source code and putting that tar file up on a download site, and (b) end-users who are getting the source code tar file, compiling that source code on their system and using the resulting binary. Obviously the folks in group (a) also compile the code and use the resulting binary, but the folks in group (b) don't have or need, often, all the tools for development that the folks in group (a) need.
So the use of the tools is geared towards this split, where the people in group (b) don't have access to autoconf, automake, etc.
When using autoconf, people generally check in the configure.ac
file (input to autoconf) into source control but do not check in the output of autoconf, the configure
script (some projects do check in the configure
script of course: it's up to you).
When using automake, people generally check in the Makefile.am
file (input to automake) but do not check in the output of automake: Makefile.in
.
The configure
script basically looks at your system for various optional elements that the package may or may not need, where they can be found, etc. Once it finds this information, it can use it to convert various XXX.in
files (typically, but not solely, Makefile.in
) into XXX
files (for example, Makefile
).
So the steps generally go like this: write configure.ac
and Makefile.am
and check them in. To build the project from source code control checkout, run autoconf to generate configure
from configure.ac
. Run automake to generate Makefile.in
from Makefile.am
. Run configure to generate Makefile
from Makefile.in
. Run make to build the product.
When you want to release the source code (if you're developing an open source product that makes source code releases) you run autoconf and automake, then bundle up the source code with the configure
and Makefile.in
files, so that people building your source code release just need make and a compiler and don't need any autotools.
Because the order of running autoconf and automake (and libtool if you use it) can be tricky there are scripts like autogen.sh and autoreconf, etc. which are checked into source control to be used by developers building from source control, but these are not needed/used by people building from the source code release tar file etc.
Autoconf and automake are often used together but you can use autoconf without automake, if you want to write your own Makefile.in
.
Solution 2
For this error:
config.status: error: cannot find input file: `somedir/Makefile.in'
In the directory where the configure.ac is located in the Makefile.am add a line with the subdirectory somedir
SUBDIRS = somedir
Inside somedir
put a Makefile.am
with all the description. then run automaker --add-missing
A better description can be found in 7.1 Recursing subdirectories automake manual. https://www.gnu.org/software/automake/manual/automake.html
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Siler
Updated on July 09, 2022Comments
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Siler over 1 year
I'm currently learning how to use the
autoconf
/automake
toolchain. I seem to have a general understanding of the workflow here - basically you have aconfigure.ac
script which generates an executableconfigure
file. The generatedconfigure
script is then executed by the end user to generateMakefile
s, so the program can be built/installed.So the installation for a typical end-user is basically:
./configure make make install make clean
Okay, now here's where I'm confused:
As a developer, I've noticed that the auto-generated configure script sometimes won't run, and will error with:
config.status: error: cannot find input file: `somedir/Makefile.in'
This confuses me, because I thought the configure script is supposed to generate the
Makefile.in
. So Googling around for some answers, I've discovered that this can be fixed with anautogen.sh
script, which basically "resets" the state of theautoconf
environment. A typicalautogen.sh
script would be something like:aclocal \ && automake --add-missing \ && autoconf
Okay fine. But as an end-user who's downloaded countless tarballs throughout my life, I've never had to use an
autogen.sh
script. All I did was uncompress the tarball, and do the usual configure/make/make install/make clean routine.But as a developer who's now using
autoconf
, it seems thatconfigure
doesn't actually run unless you runautogen.sh
first. So I find this very confusing, because I thought the end-user shouldn't have to runautogen.sh
.So why do I have to run
autogen.sh
first - in order for the configure script to findMakefile.in
? Why doesn't the configure script simply generate it?-
Admin almost 9 yearsGNU Autoconf (or perhaps GNU Automake) comes with a convenient
autoreconf
script that does the same thing asautogen.sh
and more. As for why you need to run it, do you have aMakefile.am
in thesomedir
subdirectory for Automake to findsomedir/Makefile.am
and generatesomedir/Makefile.in
from it? -
jww over 4 yearsIf there is an
autoreg.sh
script, then run it. If not, then runautoupdate && autoreconf -f -i
. Both should produce aconfigure
for you to run. It is sad it is not clearly stated in the Autotools manuals, but it is par for the course with Autotools. By the way, I believeautogen.sh
is a wrapper script forautoreconf -f -i
(maybe with a verbose option).
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