I have a series of directories organized like this:
foo/
foo.file1 foo.file2
bar/
bar.file1 bar.file2
baz/
baz.file1 baz.file2
Right now I'm processing these files using a script that does all the checking for file existence etc but I thought that perhaps I could use a Makefile for it (since said script is very fragile), to avoid reprocessing files that did not change.
The problem is that each directory is independent, and I'd need to do, for example:
foo.file1.processed: foo.file1
run_random_program foo.file1 -o foo.file1.processed
for each of the 71 directories that are in total in that path. This looks like being extremely tedious and I wonder if there's something that would prevent me from writing all of this by hand.
Is such a thing possible?
EDIT: Some examples that show what I have in mind, had I a single Makefile for each directory:
file1.cds.callable: file1.callable
long_script_name -i $< -o $#
file1.rds: file1.cds.callable
another_long_script_name $< additional_file_in_folder $#
file1.csv: file1.rds
yet_another_script $< $#
Seems like pattern rules are exactly what you need:
# These are the original source files (based on the example)
CALLABLE := $(wildcard */*.callable)
# These are the final targets
TARGETS := $(CALLABLE:%.callable=%.csv)
all: $(TARGETS)
%.csv : %.rds
yet_another_script $< $#
%.rds: %.cds.callable
another_long_script_name $< additional_file_in_folder $#
%.cds.callable: %.callable
long_script_name -i $< -o $#
I would like to copy pdf files from several directories into a build directory, then use pdfunite to compile them into one pdf. The following make recipe works, but I have to run it twice because the first time through, I get an error from pdfunite - no files are found in the build directory (the PDFS variable is empty) even though they were just copied in the previous lines. How can I fix this so it works in one pass? I have simplified the recipe for clarity; I am actually pulling from various folders and making some pdfs on the fly as well, so I can't easily concatenate a full list of files from various subfolders (folder1 and folder2 in the example) to pass to pdfunite.
notebook:
mkdir -p $(out)
mkdir -p $(build)/notebook
$(eval PR := $(sort $(wildcard $(data)/folder1/*.pdf)) )
cp $(PR) $(build)/notebook
$(eval SR := $(sort $(wildcard $(data)/folder2/*.pdf)) )
cp $(SR) $(build)/notebook
$(eval PDFS := $(sort $(wildcard $(build)/notebook/*.pdf)) )
pdfunite $(PDFS) $(out)/notebook.pdf
Your Makefile is not in line with make's philosophy. You are using make as another scripting language, while make is more than this. It compares targets and prerequisites dates, based on this decides which must be built or re-built, and passes the recipes to the shell. So, for your particular problem, you should rather try something like:
PR := $(wildcard $(data)/folder1/*.pdf)
SR := $(wildcard $(data)/folder2/*.pdf)
PDFS1 := $(patsubst $(data)/folder1/%.pdf,$(build)/notebook/%.pdf,$(PR))
PDFS2 := $(patsubst $(data)/folder2/%.pdf,$(build)/notebook/%.pdf,$(SR))
PDFS := $(sort $(PDFS1) $(PDFS2))
.PHONY: notebook
notebook: $(out)/notebook.pdf
$(PDFS1): $(build)/notebook/%.pdf: $(data)/folder1/%.pdf | $(build)/notebook
cp $< $#
$(PDFS2): $(build)/notebook/%.pdf: $(data)/folder2/%.pdf | $(build)/notebook
cp $< $#
$(build)/notebook $(out):
mkdir -p $#
$(out)/notebook.pdf: $(PDFS) | $(out)
pdfunite $(PDFS) $#
The variables definitions are reasonably straightforward: patsubst, as its name says, substitutes strings. The target: pattern: prerequisites is a static pattern rule. And the prerequisites after | are order-only prerequisites.
What this makefile says, basically, is that $(out)/notebook.pdf depends on a set of pdf files in $(build)/notebook/ and that these pdf files depend on source pdf files with the same basenames in $(data)/folder1/ and $(data)/folder2/. It also says that directories must be created before being populated. Thanks to all this only what needs to be done will be done, no more, no less. And it is more in line with make's philosophy.
If you have many source folders and do not want to replicate the copying rules, you can use more advanced features like:
FOLDERS := folder1 folder2
.PHONY: notebook
notebook: $(out)/notebook.pdf
define MY_rule
$(1)_SRCS := $$(wildcard $$(data)/$(1)/*.pdf)
$(1)_DSTS := $$(patsubst $$(data)/$(1)/%.pdf,$$(build)/notebook/%.pdf,$$($(1)_SRCS))
PDFS += $$($(1)_DSTS)
$(1)_DSTS: $$(build)/notebook/%.pdf: $$(data)/$(1)/%.pdf | $$(build)/notebook
cp $$< $$#
endef
$(foreach f,$(FOLDERS),$(eval $(call MY_rule,$(f))))
$(build)/notebook $(out):
mkdir -p $#
$(out)/notebook.pdf: $(PDFS) | $(out)
pdfunite $(PDFS) $#
I would do another way.
PR:=$(sort $(wildcard $(data)/folder1/*.pdf))
SR:=$(sort $(wildcard $(data)/folder2/*.pdf))
PDFS=$(sort $(wildcard $(build)/notebook/*.pdf))
all: copy
pdfunite $(PDFS) $(out)/notebook.pdf
copy:
mkdir -p $(out)
mkdir -p $(build)/notebook
cp $(PR) $(build)/notebook
cp $(SR) $(build)/notebook
.PHONY: all copy
Please check: PDFS= and not PDFS:=. If you use simple = the variable's value will calculate when it needed (not sooner!).
When you run make it want to build all. The all's requirement is copy - so make does some mkdir and cp. After it return the all: the value of PDFS is needed so will evalute now - we have many-many pdf in $(build)/notebook :)
This question is different from the one at makefiles - compile all c files at once in the sense that I have one extra requirement: I want to redirect all the object files in a separate directory.
Here is the setup:
I have multiple sources in a directory say src/mylib.
I want the objects files to end up in build/mylib.
Please note also that under mylib there are subdirectories.
The first attempt was as follows:
sources = $(shell find src/ -name ".c")
objects_dirs = $(subst src/, build/, $(dir $(sources)) # This variable is used by the build rule to create directories for objects files prior to compilation
objects = $(subst src/, build/, $(patsubst %.c, %.o, $(sources))) # This variable has the paths to the objects files that will be generated in the build directory
# This is where things aren't working as expected
$(objects): build $(sources)
$(cc) $(cflags) -o $# $(word 2, $^))
build:
$(foreach dir, $(objects_dirs), $(shell mkdir -p $(dir)))
For the makefile above, only one object file was being generated. I guessed this might have something to do with GCC only being able to generate one object file at a time. Regardless of that, checking the values of $# and $(word 2, $^) in the $(objects) target shows that only one file is being considered even though I have multiple files.
So I changed my makefile to the following:
sources = $(shell find src/ -name ".c")
objects = $(subst src/, build/, $(patsubst %.c, %.o, $(sources))) # This variable has the paths to the objects files that will be generated in the build directory
# This works as expected but it appears to me like make is generating all the objects files even though source files did not change. This can be seen by checking the timestamps on new object files after running make again.
$(objects): build $(sources)
$(foreach source, $(sources), $(shell $(cc) $(cflags) -o $(subst src/,build/, $(patsubst %.o,%.c,$(source))) $(source)))
build:
$(foreach dir, $(objects_dirs), $(shell mkdir -p $(dir)))
The second makefile works as expected but objects files are being rebuilt again which defeats another purpose of using make: only recompile those source files that changed from the last compilation.
Hence my question: how does one generate all object files in a separate directory at once (by this I mean perform the compilation of all sources files in one rule) while making sure that if a source file didn't change the associated object file should not be regenerated.
I am not after speeding up compilation. What I seek is one rule that will generate all objects files such that only updated source files should be recompiled.
The last makefile does the job but there is a recompiling of all source files which defeats another purpose of using make: only changed source files should be recompiled.
EDIT
After reading comments, it appears I have not phrased my question properly. As the details of what I have are already present, I leave the question as it is with additional details below.
The second makefile in the source code above does work. But it does only half the job. The build directory effectively mirrors the src directory.
So if I have say a file as src/mylib/point/point.c, I get build/mylib/point/point.o generated. This is the first part.
The second part is that if point.c does not changes, point.o in the build/mylib/point/ directory must not be regenerated. But after checking timestamps on the object file, I can tell that a new object file replaced the old one after running make again. This is not good because for large projects, compilation time remains O(n) with n being the number of source files to compile.
So this question is about how to preserve the second makefile without make regenerating object files.
From what I can gather from comments, I am asking too much from make. But if anyone knows how to make this happen, I leave the question open.
Makefile:
all:
clean:
src_root := src
src_subdirs := foo foo/bar foo/bar/buz
build_root := build
o_suffix := .o
# Build list of sources. Iterate every subfolder from $(src_subdirs) list
# and fetch all existing files with suffixes matching the list.
source_suffixes := .c .cpp .cxx
sources := $(foreach d,$(addprefix $(src_root)/,$(src_subdirs)),$(wildcard $(addprefix $d/*,$(source_suffixes))))
# If src_subdirs make variable is unset, use 'find' command to build list of sources.
# Note that we use the same list of suffixes but tweak them for use with 'find'
ifeq ($(src_subdirs),)
sources := $(shell find $(src_root) -type f $(foreach s,$(source_suffixes),$(if $(findstring $s,$(firstword $(source_suffixes))),,-o) -name '*$s'))
endif
$(info sources=$(sources))
# Build source -> object file mapping.
# We want map $(src_root) -> $(build_root) and copy directory structure
# of source tree but populated with object files.
objects := $(addsuffix $(o_suffix),$(basename $(patsubst $(src_root)%,$(build_root)%,$(sources))))
$(info objects=$(objects))
# Generate rules for every .o file to depend exactly on corresponding source file.
$(foreach s,$(sources),$(foreach o,$(filter %$(basename $(notdir $s)).o,$(objects)),$(info New rule: $o: $s)$(eval $o: $s)))
# This is how we compile sources:
# First check if directory for the target file exists.
# If it doesn't run 'mkdir' command.
$(objects): ; $(if $(wildcard $(#D)),,mkdir -p $(#D) &&) g++ -c $< -o $#
# Compile all sources.
all: $(objects)
clean: ; rm -rf $(build_root)
.PHONY: clean all
Environment:
$ find
.
./src
./src/foo
./src/foo/bar
./src/foo/bar/bar.cxx
./src/foo/bar/buz
./src/foo/bar/buz/buz.c
./src/foo/bar/foo.c
./src/foo/foo.cpp
Run makefile:
$ make -f /cygdrive/c/stackoverflow/Makefile.sample -j
sources=src/foo/bar/bar.cxx src/foo/bar/buz/buz.c src/foo/bar/foo.c src/foo/foo.cpp
objects=build/foo/bar/bar.o build/foo/bar/buz/buz.o build/foo/bar/foo.o build/foo/foo.o
New rule: build/foo/bar/bar.o: src/foo/bar/bar.cxx
New rule: build/foo/bar/buz/buz.o: src/foo/bar/buz/buz.c
New rule: build/foo/bar/foo.o: src/foo/bar/foo.c
New rule: build/foo/foo.o: src/foo/bar/foo.c
New rule: build/foo/bar/foo.o: src/foo/foo.cpp
New rule: build/foo/foo.o: src/foo/foo.cpp
mkdir -p build/foo/bar && g++ -c src/foo/bar/bar.cxx -o build/foo/bar/bar.o
mkdir -p build/foo/bar/buz && g++ -c src/foo/bar/buz/buz.c -o build/foo/bar/buz/buz.o
mkdir -p build/foo/bar && g++ -c src/foo/bar/foo.c -o build/foo/bar/foo.o
mkdir -p build/foo && g++ -c src/foo/bar/foo.c -o build/foo/foo.o
Environment again:
$ find
.
./build
./build/foo
./build/foo/bar
./build/foo/bar/bar.o
./build/foo/bar/buz
./build/foo/bar/buz/buz.o
./build/foo/bar/foo.o
./build/foo/foo.o
./src
./src/foo
./src/foo/bar
./src/foo/bar/bar.cxx
./src/foo/bar/buz
./src/foo/bar/buz/buz.c
./src/foo/bar/foo.c
./src/foo/foo.cpp
Try running this Makefile with 'src_subdirs=' to exercise another approach to locate sources. Output should be the same.
I finally had some time to experiment with this, so here is what I came up with:
BUILD_DIR = build
SRC_DIR = src
SOURCES = $(shell find $(SRC_DIR)/ -name "*.c")
TARGET = program
OBJECTS = $(SOURCES:$(SRC_DIR)/%.c=$(BUILD_DIR)/%.o)
default: $(TARGET)
.SECONDEXPANSION:
$(OBJECTS) : $$(patsubst $(BUILD_DIR)/%.o,$(SRC_DIR)/%.c,$$#)
mkdir -p $(#D)
$(CC) -c -o $# $(CFLAGS) $<
$(TARGET): $(OBJECTS)
$(CC) -o $# $(CFLAGS) $^
.PHONY: default
Points of interest:
I had to change the sources find pattern from ".c" to "*.c", I'm not sure if it depends on the exact shell used, but if you want to stay portable, be sure to use a widely accepted pattern.
The .SECONDEXPANSION: is needed to enable the $$ rules for GNU Make. It is needed to allow target based substitution rules in the prerequisites for the $(OBJECTS).
The prerequisite $$(patsubst $(BUILD_DIR)/%.o,$(SRC_DIR)/%.c,$$#) is saying, that the current target depends on a specific source file with the same folder structure and name.
The command mkdir -p $(#D) is ensuring, that the path of the current target is created if it's missing.
If all you want is a single rule to handle all object files, without necessarily needing to "compile all at once" then you could have something like this:
BUILD_DIR = build
SOURCES = ...
TARGET = ...
OBJECTS = $(SOURCES:%.c=$(BUILD_DIR)/%.o)
default: target
target: $(TARGET)
$(TARGET): $(OBJECTS)
$(LD) -o $# $(LDFLAGS) $^ $(LIBS)
$(BUILD_DIR)/%.o: %.c
$(CC) -c -o $# $< $(CFLAGS)
$(BUILD_DIR):
-mkdir $#
[Note: This is written from memory and without testing.]
After reading the GNU make manual again, here is a solution that solves the second problem.
The first attempt was the correct path. And the second attempt has the $(sources) in the prerequisites but does not use it in the commands and this is silly.
So the working makefile follows. It puts object files in a separate directory and it only compiles files that have changed.
sources = $(shell find src/ -name ".c")
$objects_dirs = $(subst src/, build/, $(dir $(sources)) # This variable is used by the build rule to create directories for objects files prior to compilation
objects = $(subst src/, build/, $(patsubst %.c, %.o, $(sources))) # This variable has the paths to the objects files that will be generated in the build directory
# This should now work as expected: object files go into their designated directories under "build/" and only updated files will be recompiled.
$(objects): build $(sources)
# After running say "make clean", make will figure out the need to run the first prerequisite.
# If we are doing a clean build, the number of prerequisites will equal the number of new prerequisites.
ifeq ($(words $?), $(words $^))
# Note the use of "$?" instead of "$^". $? is used since it holds prerequisites that are newer than the target while $^ will holds all prerequisites whether they are new or not.
$(foreach source, $(wordlist 2, $(words $?), $?), $(shell $(cc) $(cflags) -o $(subst src/,build, $(patsubst %.c,%.o, $(source))) $(source)))
else
# If we have a few new targets, no need to exclude "build" from prerequisites because the first prerequisite will be a file that changed.
$(foreach source, $?, $(shell $(cc) $(cflags) -o $(subst src/,build, $(patsubst %.c,%.o, $(source))) $(source)))
endif
.PHONY: build
build:
$(foreach dir, $(objects_dirs), $(shell mkdir -p $(dir)))
.PHONY: clean
clean:
#rm -rf build/
The makefile is heavily commented with changes that made it work. The most important changes were:
Use of $(foreach) to compile each file individually as required by GCC
Use of $? to work only with prerequisites that are newer than the target
Use of conditional to detected whether the first prerequisite has changed depending on circumstances. If we have a clean build (running make for the first time or after running make clean), the number of updated prerequisites will be the same as the number of newer prerequisites compared to the target. In other words $(words $?) == $(words $^) will be true. So we use this fact to exclude the firs prerequisite listed (build in our case) from the list of files to pass to GCC.
Also, when building the executable from the objects files, make sure to use $^ and not $? when selecting prerequisites else you will end up with only newer files in the executable and it will not run.
target = bin/mylib.a
.PHONY: all
all: $(target)
$(target): $(objects)
ar -cvq $# $^ # Notice that we're not using $? else only updated object files will end up in the archive.
I have a compiler that produces .c files from .ec files as an intermediate step. The compiler does not remove the .c file. The compiler cannot be asked to skip invocation of $CC to produce the .o file. I am trying to have GNU make (3.81) treat the .c files produced as intermediate files and clean them up. The following is an isolated example that reproduces the bad behavior with a file extension that has no implied rules.
.INTERMEDIATE: %.delme
%.o: %.ec
cp $< $(<:.ec=.delme)
cp $(<:.ec=.delme) $#
all: test.o
To execute the test case:
rm -f test.*
touch test.ec
make
if [[ -e test.delme ]]; then echo "Failure"; else echo "Success"; fi
Try using a pattern rule to tell make their your compiler produces both .o and .c files from the .ec source. And then declare all the c files as INTERMEDIATE. Pattern rules with multiple outputs work differently than non-pattern rules. Make will run pattern rules only once to produce all output files from the rule, while static rules will be run for each output file. Make also understand that a pattern rule will produce all output files, even if it only wanted one of them as a target.
The result is something like this:
SRC := foo.ec bar.ec
OBJS := $(SRC:.ec=.o)
all: program
program: $(OBJS)
cat $^ > $#
%.o %.c: %.ec
cp $< $(<:.ec=.c) ; cp $< $(<:.ec=.o)
.INTERMEDIATE: $(SRC:.ec=.c)
The command to make the .c and .o from the .ec will be run once to produce both those files. Since make knows it made the .c (even though it only wanted the .o), it will know enough to delete it. The .INTERMEDIATE target will only work if the files are listed explicitly, not using a pattern, so we haven't used %.c. Which seems like a bad idea anyway, what if you had C source that wasn't produce from an .ec file and make deleted it for you? Example output:
$ make
cp foo.ec foo.c ; cp foo.ec foo.o
cp bar.ec bar.c ; cp bar.ec bar.o
cat foo.o bar.o > program
rm bar.c foo.c
$ touch foo.ec ; make
cp foo.ec foo.c ; cp foo.ec foo.o
cat foo.o bar.o > program
rm foo.c
Notice how in the second invocation it only deleted foo.c since bar.o/c wasn't rebuilt.
Make can only consider make targets to be intermediate. You can't just declare a random file on the filesystem as intermediate and have make delete it for you.
Here the .delme file is created as a side effect of the recipe that builds the .o file; make doesn't know anything about it, so make will not delete it because there are no targets in the makefile that are intermediate.
In your example you could split the two cp commands into separate rules and that would allow the intermediate setting to work:
%.delme : %.ec
cp $< $#
%.o : %.delme
cp $< $#
I'm assuming that in your real environment you can't do that because it's all one command that generates the intermediate file and the real file. In that case you'll have to deal with the delete yourself inside the recipe:
%.o : %.ec
cp $< $(<:.ec=.delme)
cp $(<:.ec=.delme) $# && rm -f $(<:.ec=.delme)
Note this leaves the .delme file existing if the cp command fails; if you want to remove it no matter what you can do that too.
EDIT
To delete the intermediate file even if the command fails you have to preserve the exit code so you can tell make what it was. Something like:
%.o : %.ec
cp $< $(<:.ec=.delme)
cp $(<:.ec=.delme) $#; e=$$?; rm -f $(<:.ec=.delme); exit $$e
I have a Makefile which generates JSON from several different Python scripts (the scripts print to stdout) in a single directory, e.g.
/src
scriptOne.py
scriptTwo.py
scriptThree.py
Which outputs the JSON to a folder:
/templates
scriptOne.json
scriptTwo.json
scriptThree.json
I'm trying to restructure so that, for example, each script is in its own subdirectory and the Makefile creates the JSON templates in their consequent subdirectories as follows:
/src
/importantTemplates
scriptOne.py
/notSoImportantTemplates
scriptTwo.py
scriptThree.py
And the output:
/templates
/importantTemplates
scriptOne.json
/notSoImportantTemplates
scriptTwo.json
scriptThree.json
The current Makefile is as follows:
SOURCES := $(shell echo src/*.py)
TARGETS := $(patsubst src/%.py,templates/%.json,$(SOURCES))
all: $(TARGETS)
clean:
rm -f $(TARGETS)
templates/%.json: src/%.py
python2 $< > $#
I've tried changing the wildcards to include a subdirectory for each line e.g. /src/*/*.py, although I just end up with the following:
make: Nothing to be done for `all'.
You want a static pattern rule (4.12 Static Pattern Rules) for this.
SOURCES := $(wildcard src/*/*.py)
TARGETS := $(patsubst src/%.py,templates/%.json,$(SOURCES))
all: $(TARGETS)
clean:
rm -rf templates
$(TARGETS) : templates/%.json: src/%.py
mkdir -p $(#D)
python2 $< > $#
You could avoid needing mkdir -p in that rule body if you wanted to (and go with an order-only prerequisite on the directory instead) but I'm not sure the effort is worth the savings in execution cost. You could avoid the extra shell by combining the two lines mkdir -p $(#D) && python2 $< > $# if you wanted to though.
Please note that the second time you run the make, it will give you the message (if there are no new files):
make: Nothing to be done for `all'.
Try to run make clean and see if you get the same message.
Here is the Makefile which will do what you want:
SOURCES := $(wildcard src/*/*.py)
TARGETS := $(patsubst src/%.py,templates/%.json,$(SOURCES))
FOLDERS := $(sort $(dir $(TARGETS)))
all: $(TARGETS)
clean:
rm -rf $(TARGETS) $(FOLDERS)
$(FOLDERS):
mkdir -p $#
$(TARGETS): $(SOURCES) $(FOLDERS)
python2 $< > $#
The FOLDERS variable will contain the folders you need to create in the template directory. (sort will remove duplicates, so each folder will be there only once)
The $(FOLDERS) rule will create the folders.
The clean rule will remove the folders also.
If you need to add more sources, just do it like this:
SOURCES := $(wildcard src/*/*.py)
SOURCES += $(wildcard src/*.py)
...