How to run target after some commands in gnumake - makefile

I have Makefile like this:
b:
#echo "b"
a:
#echo "a"
#make b
I want this Makefile to print "a\nb" after i execute 'make a'. It does the
thing, but It also prints "Entering directory" and "Leaving directory":
$ make a
a
make[1]: Entering directory `/home/bessarabov'
b
make[1]: Leaving directory `/home/bessarabov'
Actually that lines doesn't disturb me, but I'm not sure that this is the
correct way of running some targets in the end of other targets.

GNU make has a switch to silence the Entering/Leaving messages: --no-print-directory. using make usually isn't right, you probably want to change it to $(MAKE).
rationale for $(MAKE) versus "make" is given in the GNU make manual here and here

Related

Pass file argument through to child make

Conditions:
a makefile is passed to the make: make -f ../makefile hi
the hi target also calls make
I need a way to propagate the value from -f to the sub-make command running inside hi.
bye:
echo 'whatever'
hi:
${MAKE} bye
Assuming there is no default makefile in the current directory
(presumably the reason you are passing -f ../makefile) then
your example ../makefile will work as it is if you invoke
make like:
$ make MAKEFILES=../makefile hi
make bye
make[1]: Entering directory '/home/imk/develop/scrap'
echo 'whatever'
whatever
make[1]: Leaving directory '/home/imk/develop/scrap'
See 3.4 The Variable MAKEFILES
If there is a default makefile in the current directory then this
approach will cause make to read the default makefile after it has
read ../makefile, with untoward results. In that case prefer #Dummy00001's answer.
The only possibility I'm aware of is to use the MAKEFILE_LIST variable:
CURR_MAKEFILE:=$(lastword $(MAKEFILE_LIST))
bye:
echo 'whatever'
hi:
+$(MAKE) -f $(CURR_MAKEFILE) bye
But note, as it is written in the official documentation, that the variable records all parsed makefiles, including the includeed ones. The value of the variable is only reliable when queried at the very top of the makefile, before any includes.

Using Make with force snippet to override other file

I've been trying to get a makefile, a, to include another makefile, b, if the target specified is not found in file a. I'm using this snippet to try and achieve this, but from echos I've put into the file I can see that makefile b is being accessed even when the target is found in a and run.
The snippet I'm using from the link above is:
foo:
frobnicate > foo
%: force
#echo "No target found locally, running default makefile"
#$(MAKE) -f Makefile $#
force: ;
Specifically I'm getting "Nothing to be done" outputs when makefile b is being used, and makefile a is behaving as expected. This is shown below:
$ make all # all target appears in both make files
No target found locally, running default makefile
make[1]: Entering directory `/home/user/currdir' # (b)
make[1]: Nothing to be done for `Makefile'.
make[1]: Leaving directory `/home/user/currdir'
Local all # (a)
Is there a better way to be doing this?
addition: After adding another echo to the % rule, I've found that $# is "Makefile", when it should be the target trying to be built.
I don't really understand your question based on the example you gave; there is no "a" or "b" in that example, just one Makefile.
However, the behavior you're seeing is due to GNU make's re-making makefiles capability. When you create match-anything pattern rules as you've done, you have to consider that every single target or prerequisite that make wants to build will match that rule. That's a large burden.
You can avoid having remade makefiles match by creating explicit rules for them, such as:
Makefile: ;

Specifying different GNUmakefile for GNU make command

I have two GNUmakefiles in my directory as follows,
GNUmakefile &
GNUmakefile2
Could someone please let me know the command I have to use, if I have to let the "make" command to process "GNUmakefile2" instead of "GNUmakefile".
I used the below command,
make -f GNUmakefile2
but in that case, I am getting the following errors,
This is gnustep-make 2.6.1. Type 'make print-gnustep-make-help' for help.
make[1]: ** No rule to make target `internal-master-tool-all'. Stop.*
make: ** [internal-all] Error 2*
I think it is considering GNUmakefile as makefile (when I use make with -f command), so it is checking for rules in GNUmakefile.
At present what I am doing is I am renaming the required file (which I want, make command to execute) to "GNUmakefile". And I am not getting any errors while executing "make" command, but I don't think this is the correct solution.
Please let me know which command I need to use for this scenario. Thanks for your help.
After checking Beta's solution (i.e.,but that makefile is invoking Make a second time, and the second Make process is probably reading GNUmakefile) what I have done is I renamed existing "GNUmakefile" to "GNUmakefile3".
So at present in my directory the following makefiles are present:- "GNUmakefile2" & "GNUmakefile3".
And then I executed the following command:- $ make -f GNUmakefile2
I recieved the below errors,
This is gnustep-make 2.6.1. Type 'make print-gnustep-make-help' for help.
make[1]: GNUmakefile: No such file or directory
make[1]: * No rule to make target `GNUmakefile'. Stop.
make: * [internal-all] Error 2
Please let me know what is the problem here
Your makefile includes two huge makefiles from the FSF. The second, library.make, contains this rule:
ifeq ($(GNUSTEP_MAKE_PARALLEL_BUILDING), no)
# Standard building
...
else
# Parallel building. ...
internal-library-all_:: $(GNUSTEP_OBJ_INSTANCE_DIR) $(OBJ_DIRS_TO_CREATE)
$(ECHO_NOTHING_RECURSIVE_MAKE)$(MAKE) -f $(MAKEFILE_NAME) ...
endif
and the first, common.make contains this assignment:
# The default name of the makefile to be used in recursive invocations of make
ifeq ($(MAKEFILE_NAME),)
MAKEFILE_NAME = GNUmakefile
endif
So try either make -f GNUmakefile2 GNUSTEP_MAKE_PARALLEL_BUILDING=no or make -f GNUmakefile2 MAKEFILE_NAME=GNUmakefile2, and see if that solves the problem.

What is the purpose of .PHONY in a Makefile?

What does .PHONY mean in a Makefile? I have gone through this, but it is too complicated.
Can somebody explain it to me in simple terms?
By default, Makefile targets are "file targets" - they are used to build files from other files. Make assumes its target is a file, and this makes writing Makefiles relatively easy:
foo: bar
create_one_from_the_other foo bar
However, sometimes you want your Makefile to run commands that do not represent physical files in the file system. Good examples for this are the common targets "clean" and "all". Chances are this isn't the case, but you may potentially have a file named clean in your main directory. In such a case Make will be confused because by default the clean target would be associated with this file and Make will only run it when the file doesn't appear to be up-to-date with regards to its dependencies.
These special targets are called phony and you can explicitly tell Make they're not associated with files, e.g.:
.PHONY: clean
clean:
rm -rf *.o
Now make clean will run as expected even if you do have a file named clean.
In terms of Make, a phony target is simply a target that is always out-of-date, so whenever you ask make <phony_target>, it will run, independent from the state of the file system. Some common make targets that are often phony are: all, install, clean, distclean, TAGS, info, check.
Let's assume you have install target, which is a very common in makefiles. If you do not use .PHONY, and a file named install exists in the same directory as the Makefile, then make install will do nothing. This is because Make interprets the rule to mean "execute such-and-such recipe to create the file named install". Since the file is already there, and its dependencies didn't change, nothing will be done.
However if you make the install target PHONY, it will tell the make tool that the target is fictional, and that make should not expect it to create the actual file. Hence it will not check whether the install file exists, meaning: a) its behavior will not be altered if the file does exist and b) extra stat() will not be called.
Generally all targets in your Makefile which do not produce an output file with the same name as the target name should be PHONY. This typically includes all, install, clean, distclean, and so on.
NOTE: The make tool reads the makefile and checks the modification time-stamps of the files at both the side of ':' symbol in a rule.
Example
In a directory 'test' following files are present:
prerit#vvdn105:~/test$ ls
hello hello.c makefile
In makefile a rule is defined as follows:
hello:hello.c
cc hello.c -o hello
Now assume that file 'hello' is a text file containing some data, which was created after 'hello.c' file. So the modification (or creation) time-stamp of 'hello' will be newer than that of the 'hello.c'. So when we will invoke 'make hello' from command line, it will print as:
make: `hello' is up to date.
Now access the 'hello.c' file and put some white spaces in it, which doesn't affect the code syntax or logic then save and quit. Now the modification time-stamp of hello.c is newer than that of the 'hello'. Now if you invoke 'make hello', it will execute the commands as:
cc hello.c -o hello
And the file 'hello' (text file) will be overwritten with a new binary file 'hello' (result of above compilation command).
If we use .PHONY in makefile as follow:
.PHONY:hello
hello:hello.c
cc hello.c -o hello
and then invoke 'make hello', it will ignore any file present in the pwd 'test' and execute the command every time.
Now suppose, that 'hello' target has no dependencies declared:
hello:
cc hello.c -o hello
and 'hello' file is already present in the pwd 'test', then 'make hello' will always show as:
make: `hello' is up to date.
.PHONY: install
means the word "install" doesn't represent a file name in this
Makefile;
means the Makefile has nothing to do with a file called "install"
in the same directory.
It is a build target that is not a filename.
The special target .PHONY: allows to declare phony targets, so that make will not check them as actual file names: it will work all the time even if such files still exist.
You can put several .PHONY: in your Makefile :
.PHONY: all
all : prog1 prog2
...
.PHONY: clean distclean
clean :
...
distclean :
...
There is another way to declare phony targets : simply put :: without prerequisites :
all :: prog1 prog2
...
clean ::
...
distclean ::
...
The :: has other special meanings, see here, but without prerequisites it always execute the recipes, even if the target already exists, thus acting as a phony target.
The best explanation is the GNU make manual itself: 4.6 Phony Targets section.
.PHONY is one of make's Special Built-in Target Names. There are other targets that you may be interested in, so it's worth skimming through these references.
When it is time to consider a .PHONY target, make will run its recipe
unconditionally, regardless of whether a file with that name exists or
what its last-modification time is.
You may also be interested in make's Standard Targets such as all and clean.
There's also one important tricky treat of ".PHONY" - when a physical target depends on phony target that depends on another physical target:
TARGET1 -> PHONY_FORWARDER1 -> PHONY_FORWARDER2 -> TARGET2
You'd simply expect that if you updated TARGET2, then TARGET1 should be considered stale against TARGET1, so TARGET1 should be rebuild. And it really works this way.
The tricky part is when TARGET2 isn't stale against TARGET1 - in which case you should expect that TARGET1 shouldn't be rebuild.
This surprisingly doesn't work because: the phony target was run anyway (as phony targets normally do), which means that the phony target was considered updated. And because of that TARGET1 is considered stale against the phony target.
Consider:
all: fileall
fileall: file2 filefwd
echo file2 file1 >fileall
file2: file2.src
echo file2.src >file2
file1: file1.src
echo file1.src >file1
echo file1.src >>file1
.PHONY: filefwd
.PHONY: filefwd2
filefwd: filefwd2
filefwd2: file1
#echo "Produced target file1"
prepare:
echo "Some text 1" >> file1.src
echo "Some text 2" >> file2.src
You can play around with this:
first do 'make prepare' to prepare the "source files"
play around with that by touching particular files to see them updated
You can see that fileall depends on file1 indirectly through a phony target - but it always gets rebuilt due to this dependency. If you change the dependency in fileall from filefwd to file, now fileall does not get rebuilt every time, but only when any of dependent targets is stale against it as a file.
I often use them to tell the default target not to fire.
superclean: clean andsomethingelse
blah: superclean
clean:
#echo clean
%:
#echo catcher $#
.PHONY: superclean
Without PHONY, make superclean would fire clean, andsomethingelse, and catcher superclean; but with PHONY, make superclean won't fire the catcher superclean.
We don't have to worry about telling make the clean target is PHONY, because it isn't completely phony. Though it never produces the clean file, it has commands to fire so make will think it's a final target.
However, the superclean target really is phony, so make will try to stack it up with anything else that provides deps for the superclean target — this includes other superclean targets and the % target.
Note that we don't say anything at all about andsomethingelse or blah, so they clearly go to the catcher.
The output looks something like this:
$ make clean
clean
$ make superclean
clean
catcher andsomethingelse
$ make blah
clean
catcher andsomethingelse
catcher blah

Makefile calling other makefile with target, gives wrong target

I have a makefile with a target clean:
clean:
$(MAKE) -f <other makefile location> clean
When I call make clean in this makefile, it tells me that in the other makefile there is no rule 'clean-linux'. Specifically here is the output.
make -f /root/ovaldi-5.5.25-src/project/linux/Makefile clean
make[1]: Entering directory '/root/ovaldi-5.5.25-src'
make[2]: Entering directory '/root/ovaldi-5.5.25-src'
make[2]: *** No rule to make target 'clean-linux'. Stop.
make[2]: Leaving directory '/root/ovaldi-5.5.25-src'
make[1]: Leaving directory '/root/ovaldi-5.5.25-src'
Why is it giving it the clean-linux target and not just clean like I specified?
When you make (or $(MAKE)), by default you use whatever makefile is there. So here's what I think is happening.
You cd to some location.
You 'make -f Makefile_A clean'.
make runs with Makefile_A, and does '$(MAKE) -f Makefile_B clean'.
make[1] runs with Makefile_B, and does '$(MAKE) clean-linux'.
make[2] runs with whatever makefile is here which might be anything (I suspect it's Makefile_A) but whatever it is it has no rule for clean-linux.
The solution: rewrite your second makefile (the one that has clean-linux) so that clean-linux becomes a prerequisite of clean (if/when you're on a linux system). That way it won't run make[2].
ifeq ($(PLATFORM), LINUX)
clean: clean-linux
endif
ifeq ($(PLATFORM), SUNOS)
clean: clean-sunos
endif
clean:;
Just a guess but maybe the 'clean' target in the second makefile calls 'clean-linux'?
Can you post the clean target of the second makefile?
Edit:
In light of your posted clean target it seems you're just calling the clean-linux target incorrectly.
Beta has posted the correct way of dealing with your problem in their answer so I'm going to +1 that.

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