How to add .inc files based on variable for recursive automake - makefile

I have the following folder structure:
Top folder
|-- configure.ac
|-- Makefile.am
|-- Folder1
| `-- Makefile.inc
`-- Folder2
`-- Makefile.inc
Only one child Makefile.inc should be included by Makefile.am, and that should be decided based on a flag passed to ./configure, e.g.:
./configure FOLDER_TO_INCLUDE=FOLDER1
This is what I have attempted:
configure.ac:
FOLDER_TO_INCLUDE=$(FOLDER_TO_INCLUDE)
AC_SUBST(FOLDER_TO_INCLUDE)
Makefile.am:
include $(srcdir)/#FOLDER_TO_INCLUDE#/Makefile.inc
However instead of the final Makefile including the child .inc content, it just contains this line:
include $(srcdir)/Folder1/Makefile.inc
Is there any way around this issue?

As you seem to appreciate, include statements are processed by Automake, not by make. What you do not seem to appreciate is that Automake's (and Autoconf's) full effect is delivered in building the build system, especially the configure script and a Makefile.in file corresponding to each Makefile.am. Thus, include statements cannot usefully depend on output variables determined by configure.
You should be able to use Automake conditionals instead. That will have pieces in both configure.ac:
AM_CONDITIONAL([INCLUDE_FOLDER1], [test "$which_folder" = "Folder1"])
and in Makefile.am:
if INCLUDE_FOLDER1
include $(srcdir)/Folder1/Makefile.inc
endif
You will need a separate conditional for each subfolder. This approach will perform the lexical inclusion when Automake runs, but in such a way that the included contents are effective only when the associated condition is satisfied at configure time.

Related

Symbols ($(bindir), $(sysconfdir),...) unknown in (sub) Makefiles

I'm working with autotools for the first time, for a tool that's written in perl (SQLTeX), so only installation is required, no compilation.
The toplevel contains a simple Makefile.am:
AUTOMAKE_OPTIONS = foreign
SUBDIRS = src man doc
EXTRA_DIST = README.md
.PHONY: all-am
all-am:
#echo "Done!"
If I create Makefile.am files in the sub-directories too, nothing seems to happen there so I just stick to Makefile. A snippet from src/Makefile (EDIT: this file is now renamed to Makefile.am):
SQLTeX: SQLTeX.pl
cat $^ | sed -e 's#{PERLDIR}#$(PL)#;s#{SYSCONFDIR}#$(sysconfdir)#' > $#
#chmod +x $#
The symbol PL is set as expect (defined in the same makefile), but sysconfdir is empty, although it is defined in the top-level Makefile generated by ./configure.
What am I doing wrong?
Thanks in advance!
What am I doing wrong?
Although the Autotools support, with some caveats, recursing into directories where you provide pre-built makefiles, you cannot expect those pre-built makefiles to be able to rely on autotools-provided variables such as the standard directory variables bindir and sysconfdir. Thus, although it is allowed to rely on hand-written makefiles in subdirectories, this is probably a false trail for you.
I recommend going back to this:
If I create Makefile.am files in the sub-directories too, nothing seems to happen there
and working out what's wrong. The Autotools definitely support generating recursive build systems, and one Makefile.am per directory is part of the usual approach to that. If it didn't work for you then my first guess would be that you forgot to list the extra makefiles in your AC_CONFIG_FILES list.
As an alternative, just because you have multiple directories does not mean that you need to use recursive make. It is quite possible to build such a project with the support of a single makefile, and the Autotools can help with such a makefile.

changing the directory and executing the makefile commands

I have the following directory structure
project
|-- aws-cdk
|-- data
|-- some_project_files
|-- Makefile
Using the Makefile, I'm executing the directory some_project_files and this is working fine. In addition to that, I want to execute aws-cdk as well. But I do not see a way to change the directory within the makefile. I tried cd aws-cdk and then execute but I keep on getting error make: *** No rule to make target. Stop.
How do I go back/change directory and then execute Makefile
Within one makefile you can change directory inside the rules, but you can't say this set of rules runs in one directory and this one runs in the other. Which does not prevent you running rules on files in a different directory by simply giving their path. The data/Makefile can contain rules for ../aws-cdk/something and even ../aws-cdk/%.out: ../aws-cdk/%.in and that's just fine.
If you do want to actually change directory, you need a separate makefile. I strongly recommend just putting it in the directory where it will run, so aws-cdk/Makefile and then you can just call it from the one in data like $(MAKE) -C ../aws-cdk. You can also put it anywhere else and give make an explicit argument like $(MAKE) -C ../aws-cdk -f aws-cdk.make, but putting it in the directory will be easier to understand when it needs fixing two years down the line and/or by someone who's never seen it.

How to create this makefile? Sources in subdirectories, separate output path, linking objects in subdirectories

Is there a way to create a makefile that does this?
I gave up after trying to follow the docs and lots of trial and error so I'll just post a description of what the makefile should do.
general directory structure:
src/ - contains c source files in various subdirectories (written manually by maintainer)
inc/ - contains h header files in subdirectories matching src (written manually by maintainer)
obj/ - contains o header files in subdirectories matching src (autogenerated by a make call)
bin/ - should contain binary (autogenerated by a make call)
makefile
so for example at a given point of time the project might look like
src/
main.c
sub1/
other1.c
other2.c
sub2/
sub3/
other3.c
inc/
sub1/
other1.h
other2.h
sub2/
sub3/
other3.h
obj/
main.o
sub1/
other1.o
other2.o
sub2/
sub3/
other3.o
bin/
release
makefile
(probably not relevant: Note that main doesn't have a header file but most likely every other c file will have a matching h file.)
I want to be able to call make, and have it:
use gcc to recompile only changed c files into respective o files in obj/, generating missing subdirectories if needed.
for example, from the above state, if I add a new subdirectory sub4 inside src/sub1/, and then create other4.c inside src/sub1/sub4/, I would like make to generate sub4 inside obj/sub1/ and then generate other4.o inside obj/sub1/sub4/
create a binary at bin/release by linking all object files (from all subdirectories in obj/)
I don't want to have to change the makefile each time I add directories in src
I don't want to manually have to create directories in obj, the makefile should take care of it. if this is not possible, maybe have it rename all obj o files to a flat naming pattern? i.e. obj/sub2_sub3_other3.o instead of obj/sub2/sub3/other3.o (although this can cause issues)
probably not relevant here, but the C files use include statements in this format:
#include "sub2/sub3/other3.h"
so -I./inc would be included in the gcc call. Whereas the linker would receive inputs like -s -O3. I want to make sure those options (compiler options, linker options) are listed at the top of the makefile in variables (CFLAGS, LDFLAGS, etc) and not passed incorrectly to the targets.
is this even possible? if not, what's the closest possible?
Also, can this makefile be made to work on both POSIX systems and on Windows based systems? e.g. work the same on linux/gcc and win/mingw

automake - target folder in source blocks executing destination

I am trying to understand a makefile from a project I am working on. It's using automake/autotools and contains this simple rule:
DEPS_SRC = $(shell cd $(srcdir); find . -name '*.ez')
DEPS = $(basename $(DEPS_SRC))
all : $(DEPS)
$(DEPS) : % : %.ez
$(UNZIP) -o $<
Say the directory structure is:
my-app/deps/
build/
When executing make my-app in the build folder the rule will basically unpack *.ez files located in the my-app/deps/ folder into build/my-app/deps/ folder.
I don't know if that's enough information to solve the problem that I am going to explain as I don't know enough about automake/autotools. Please ask if any additional information is needed.
The problem is that I noticed that having the unpacked directory in the source folder prevents make from unpacking the archive in the target folder. For example, given the following structure in the source folder:
my-app/deps/archive1.ez
my-app/deps/archive2.ez
my-app/deps/archive2/
make will only unpack archive1.ez in the build folder:
build/my-app/deps/archive1/
I would like to know if this is a bug in my makefile or a feature of automake. If the later, is there any workaround or setting or variable available to disable it?
This is primarily a GNU make question, not particularly specific to the Autotools. However, since the target system's make is of GNU's flavor (else none of this works), we can assume that the Makefile generated by configure uses GNU make's VPATH feature as part of its support for out-of-source (a.k.a. VPATH) builds such as the one you are performing.
The value of the VPATH variable that configure will have inserted into the Makefile is used as a search path for prerequisites that are not found relative to the build directory. The key point, however, is that it is also used as a search path for rule targets. That makes a certain amount of sense, especially for targets that are prerequisites of other rules.
In your case, however, that leads directly to the behavior you describe:
the default target depends on ./my-app/deps/archive2
resolving that name against the build directory does not produce a valid file name
before attempting to build that target, make looks in the directories listed in the VPATH, which, in your example case, will contain .. or an equivalent
make finds .././my-app/deps/archive2 in this VPATH search, and therefore determines that the specified target already exists, and does not need to be built
Thus, the behavior you observe is normal for GNU make, supposing the Makefile is constructed by Autoconf from an Automake-generated template.
is there any workaround or setting or variable available to disable it?
Do you really need one? If the archive file has already been unpacked in the source tree, then you can expect make to find its contents, too, via the VPATH. At least if the Makefile is well-prepared overall for for out-of-source builds.
But if you want to be certain to get the archive files unpacked in the build directory then you can specify that explicitly. This ought to do it:
DEPS_SRC = $(shell cd $(srcdir); find . -name '*.ez')
DEPS = $(basename $(DEPS_SRC))
LOCAL_DEPS = $(addprefix $(abs_builddir)/,$(DEPS))
all : $(LOCAL_DEPS)
$(LOCAL_DEPS) : $(abs_builddir)/% : %.ez
$(UNZIP) -o $<
That prefixes the name of each dependency with the absolute path to the build directory, and updates the rule for unzipping the archives to accommodate it. Targets with absolute paths such as that cannot be located in the VPATH.

Default Makefile for Sphinx

I'm trying to understand the Makefile that is automatically produced by sphinx-quickstart. Here it is:
SPHINXOPTS =
SPHINXBUILD = sphinx-build
SPHINXPROJ = myproj
SOURCEDIR = source
BUILDDIR = build
.PHONY: help Makefile
%: Makefile
#$(SPHINXBUILD) -M $# "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
The lines that confuse me are:
.PHONY: help Makefile
%: Makefile
I think I understand:
The % target means capture anything (wildcard). E.g., if I typed make html, % would capture html.
.PHONY Makefile means that make shouldn't look for a file called Makefile in its directory, thus, shouldn't check the file's modified time to determine whether or not to run a rule.
I don't understand:
Why Makefile is listed as a prerequisite for the target %. The way I interpret this is:
The target rule captured by % should run when the Makefile is changed.
But that doesn't make any sense in the context. What I would expect is:
The target rule captured by % should run when the source files for the project documentation or the API source files have changed.
Directory structure
.
├── build
├── Makefile
├── source
└── utils
The .PHONY: foo has the effect that foo is never to be considered up-to-date. (but see https://www.gnu.org/software/make/manual/html_node/Phony-Targets.html for the more detailed explanations: the main use is for targets which are not filenames)
If you then have bar: foo, the rules for bar target will always be executed on make bar because the target depends upon foo but foo is considered never up-to-date. This can also be achieved with declaring bar target to be PHONY itself.
The problem with the catch-all % target was in case the repertory where the Makefile is located contained a repertory or a file having same name as a Sphinx builder. Say for example there is an html or a man in repertory where Makefile is located: then make html will not do anything if % has no dependencies, because html is then a file or repertory with no dependencies, hence never to get updated.
Thus the % was made to depend on Makefile pseudo target, and Makefile itself declared PHONY so that it is considered never up-to-date.(*) Even if repertory contains a file html then make html will get executed (and html repertory in build dir modified; the html in Makefile repertory will not be modified).
(*) edit: I had forgotten the exact details: Makefile is always considered a target, see a surprising (?) behaviour of GNU Make when using ``%`` as target. For reasons explained here % was made to depend upon Makefile, and the Makefile was declared PHONY in fact to avoid make complaining about circular dependency...
The idea is that the Makefile should not contain the hard-coded list of all possible builders: else they could have been declared PHONY targets individually, but then Sphinx maintainers would have to worry about keeping the Makefile template up-to-date when adding a new builder. It would also cause problems when projects keep same Makefile but a new Sphinx release adds a new builder.
The Makefile now created by sphinx-quickstart does not have to be modified if a new builder is added to Sphinx. It is of course certain that never will Makefile be the name of a builder...

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