Why is the make target up to date even when using .phony? - makefile

I have a Makefile that looks like this:
RENDER_HTML=jupyter nbconvert --execute --to html
MATE40001_TARGETS=$(wildcard MATE40001/notes/*.ipynb)
.phony: all
all: MATE40001
.phony: variables
variables:
#echo MATE40001_TARGETS:
#echo ${MATE40001_TARGETS} | sed 's/ /\n/' | sed 's/MATE/\tMATE/'
.phony: MATE40001
MATE40001: ${MATE40001_TARGETS}
mkdir -p $#/html/
${RENDER_HTML} $^
mv $#/notes/*.html $#/html/
.phony: clean
clean:
rm -rf */html/ *~ */notes/*.html
When I run:
make
make clean
make
make MATE40001
I get the following output:
...
<normal output>
...
rm -rf */html/ *~ */notes/*.html
make: Nothing to be done for 'all'.
make: 'MATE40001' is up to date.
As far as I understand, make is looking for the file MATE40001 which exists as a folder and then stops because there are no updated files. However I do not want this to happen, and I thought that adding .phony: MATE40001 would stop this problem.
What do I need to add/change to fix this issue?

from comment by #G.M.
Use .PHONY instead of .phony

Related

Simple makefile command not found

I was given a makefile that looks like this, and told not to change it.
all: clean flex scanner.lex bison -d parser.ypp g++ -std=c++11 -o hw2 *.c *.cpp clean: rm -f lex.yy.c rm -f parser.tab.*pp rm -f hw2
I am trying to run this makefile in a folder with files named: scanner.lex, parser.ypp, output.hpp and output.cpp
I copied it to a file like this:
all:
clean flex scanner.lex bison -d parser.ypp g++ -std=c++11 -o hw2 *.c *.cpp
clean:
rm -f lex.yy.c rm -f parser.tab.*pp rm -f hw2
When I run the make command in my terminal I get an error:
clean flex scanner.lex bison -d parser.ypp g++ -std=c++11 -o hw2 *.c *.cpp
/bin/sh: clean: command not found
make: *** [all] Error 127
Am I doing something wrong? Again, I was given this line and told not to change it.
Thanks a lot.
Line breaks are essential in most computer environments. If you were given a Makefile without the line breaks and you try to cut it randomly you will have difficulties before if finally works. Try this, maybe:
all: clean
flex scanner.lex
bison -d parser.ypp
g++ -std=c++11 -o hw2 *.c *.cpp
clean:
rm -f lex.yy.c
rm -f parser.tab.*pp
rm -f hw2
And use tabs to indent the indented lines, not spaces.
Explanations: all and clean are what is called a target in make parlance. They are the names of the things you want make to do. clean to delete some files, all to do everything else. The
target: prerequisite1 prerequisite2...
recipe1
recipe2
...
template is the basic make template. It means that target depends on prerequisite1, prerequisite2 and that in order to build it make shall pass recipe1 to the shell for execution, then recipe2...
Note that this Makefile is poorly written. As all and clean are not real file names they should be declared as phony, such that, if a file with that name exists make does the job anyway. As is, it wouldn't. Give it a try:
$ make all
$ touch clean
$ make clean
make: 'clean' is up to date.
See? Because a file named clean exists you cannot make clean anymore, make considers that there is nothing to do for clean. Add this at the beginning of your Makefile:
.PHONY: all clean
A second issue is that make works by comparing last modification times of targets and prerequisites to decide if targets must be rebuilt or not. With your Makefile make will always recompile everything, even if the inputs did not change and the outputs are up-to-date. This is a waste. A better (but untested) Makefile would be something like:
.PHONY: all clean
CFILES := $(filter-out lex.yy.c,$(wildcard *.c))
CPPFILES := $(filter-out parser.tab.cpp,$(wildcard *.cpp))
all: hw2
hw2: lex.yy.c parser.tab.cpp $(CFILES) $(CPPFILES)
g++ -std=c++11 -o $# $^
lex.yy.c: scanner.lex
flex $<
parser.tab.cpp: parser.ypp
bison -d $<
clean:
rm -f lex.yy.c
rm -f parser.tab.*pp
rm -f hw2
Understanding it and why it is better is left as an exercise.

Is there any way to make multiple targets as series of single make invocations?

I have the following Makefile:
ifneq ($(MAKECMDGOALS),clean)
-include generated.mk
endif
FOO ?= foo
all: a.txt
a.txt:
echo $(GEN_FOO) > $#
generated.mk: Makefile
echo GEN_FOO = $(FOO) > $#
.PHONY: clean
clean:
$(RM) a.txt
$(RM) generated.mk
It works OK when building single targets:
$ make clean
rm -f a.txt
rm -f generated.mk
$ make all
echo GEN_FOO = foo > generated.mk
echo foo > a.txt
However when I try to build multiple targets at once things go not so smooth:
$ make clean all
rm -f a.txt
rm -f generated.mk
echo foo > a.txt
$ make all
echo GEN_FOO = foo > generated.mk
make: Nothing to be done for 'all'.
It gets even worse if variables were provided:
$ make clean
rm -f a.txt
rm -f generated.mk
$ make FOO=bar clean all
echo GEN_FOO = bar > generated.mk
rm -f a.txt
rm -f generated.mk
echo bar > a.txt
$ make all
echo GEN_FOO = foo > generated.mk
make: Nothing to be done for 'all'.
$ make FOO=bar clean all
rm -f a.txt
rm -f generated.mk
echo foo > a.txt
Are there any ways to fix such incorrect behavior?
Make is doing exactly what you told it to do, and you haven't told us what you want it to do that's different than what you told it to do (saying fix such incorrect behavior doesn't really help us when you don't define what's incorrect about the behavior), so we can't help you very much.
You are probably getting confused about the interaction between included makefiles and comparing $(MAKECMDGOALS). Please note:
ifneq ($(MAKECMDGOALS),clean)
this will not match unless you specify exactly one target: clean. In situations where you specify multiple targets, one of which is clean, that will match because clean all is not equal to clean. So, when you run make clean all make will include the generated makefile, and will generate it if it doesn't exist.
Because generated include files are only rebuilt once, when the makefile is first parsed, it's not possible to say something like: "first run rule X (e.g., clean) then rebuild the included makefiles, then reinvoke make".
However, it's pretty much always a bad idea to invoke make with clean all. This is because if you were to ever try to add -j for parallelism, the clean and the build would be running in parallel and corrupt everything.
One semi-common option is to provide a different rule that will do both, something like this:
rebuild:
$(MAKE) clean
$(MAKE) all
then run make rebuild instead.
You can certainly force the behavior with the help of the shell. For instance, in bash you could use
for target in "clean" "all";
do
make $target;
done
and if you were going to re-do the procedure a lot you could either make it an executable script or wrap it in a shell function.

Impose an order for Order-only-prerequisites of a target

I have a makefile snippet:
all: $(objects)
fresh: all | clean directory
directory: ;mkdir -p OutputDirectory
clean: ;rm $(objects); rm -rf OutputDirectory
Here, I want to ensure that when I do make fresh - clean should succeed by directory which should be followed by all.
Semantically, here it might not make sense for clean to be order only prerequisite. Assume it to some order only dependency that has to be executed in some order.
The following link shows similar problem but for normal dependencies:
makefile - Impose an order for the prerequisites of a target - Stack Overflow
In fresh's recipe, you could call make twice recursively on the same makefile, for the target that creates the directory and the all target, respectively:
# At the very beginning of the makefile
CURRENT_MAKEFILE := $(lastword $(MAKEFILE_LIST))
# ...
.PHONY: all clean fresh
directory := OutputDirectory
all: $(objects)
fresh: clean
$(MAKE) -f $(CURRENT_MAKEFILE) $(directory)
$(MAKE) -f $(CURRENT_MAKEFILE) all
$(directory): ;mkdir -p $#
clean: ;rm -f $(objects); rm -rf $(directory)
This way, the target all is preceded by the target $(directory), which is in turn preceded by clean.

Simple Makefile doesn't clean

I have this Makefile:
default:
mv presentacion.pdf /tmp
pdflatex presentacion.tex
clean:
rm -f *.{aux,log,nav,out,snm,toc}
The order make works well but when I try to do a make clean the shell outputs:
rm -f *.{aux,log,nav,out,snm,toc}
And does not remove the files. What's wrong in the code?
Try to set the shell to bash in your makefile (according docs)
SHELL=/bin/bash
default:
mv presentacion.pdf /tmp
pdflatex presentacion.tex
clean:
rm -f *.{aux,log,nav,out,snm,toc}
You can let make add the prefix to your files (instead of bash), by using addprefix:
PREFIXES := aux log nav out snm toc
FILES := $(addprefix *., $(PREFIXES))
default:
mv presentacion.pdf /tmp
pdflatex presentacion.tex
clean:
rm -f $(FILES)

Makefile: rule that match multiple patterns

I have this rule in my Makefile, that responds to flags I pass:
$(BUILD_DIR)/disable_%:
mkdir -p $(BUILD_DIR)
touch $(BUILD_DIR)/disable_$*
rm -f $(BUILD_DIR)/enable_$*
cd $(BUILD_DIR) && rm -f Makefile
$(BUILD_DIR)/enable_%:
mkdir -p $(BUILD_DIR)
touch $(BUILD_DIR)/enable_$*
rm -f $(BUILD_DIR)/disable_$*
cd $(BUILD_DIR) && rm -f Makefile
What this means is that when changing the flags by which I invoke the makefile, I can trigger some recompilations that could depend on these flags.
The code presented above is a bit redundant: you see that I remove a file, touch another and remove a Makefile in both cases. The only thing that changes is the name of the files that I touch/remove, and they are related.
For instance,
make clean
make enable_debug=yes enable_video=no # will compile from zero
make enable_debug=no enable_video=no # flag change detected -> recompile some submodules that depend on this flag
Provided that the only thing that changes between the two rules ( [en|dis]able ), what I would like is to only have 1 generic rule, something like that:
# match 2 parts in the rule
$(BUILD_DIR)/%ble_%:
mkdir -p $(BUILD_DIR)
touch $(BUILD_DIR)/(???)ble_$* # should be $#
rm -f $(BUILD_DIR)/(???)able_$* # should be disable if $# is enable and inverse
cd $(BUILD_DIR) && rm -f Makefile
Is this possible ?
PS: Sorry if I didn't get the title correctly, I couldn't figure how to explain it better.
$(BUILD_DIR)/enable_% $(BUILD_DIR)/disable_%:
mkdir -p $(BUILD_DIR)
rm -f $(BUILD_DIR)/*able_$*
touch $#
cd $(BUILD_DIR) && rm -f Makefile
Not literally what you wanted (multi-wildcards are forbidden in make), but does quite the same.

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