How to creat only object file without executable? - object

I am trying to create an object file through a make file which will be called in another script.
The following is my make file for creating an object file.
SOURCE_CK = ../SOURCES_COUNTERFLOW/
SOURCES_f77 = $(SOURCE_CK)density.f
#TARGET =
OBJECTS = $(SOURCES_f77:.f=.o)
COMPILE = f77
.f.o :
$(COMPILE) -o $*.o -c $*.f
#$(TARGET) : $(OBJECTS)
# $(COMPILE) $(OBJECTS) -o $#
#del :
# /bin/rm $(OBJECTS)
When I run the above script, the following error gets generated.
make: *** No targets. Stop.
Now I know I have to make some modification with TARGET but not sure where to start or how to modify the target.
Again, my goal is to run the script and generate density.o file.
Any help would be appreciated.

GNU Make has built-in rules for making fortran object files from sources, and fortran programs from object files, see https://www.gnu.org/software/make/manual/html_node/Catalogue-of-Rules.html
Your makefile can therefore be condensed into just the following:
$(TARGET): $(OBJECTS)
Should you want to generate just the object, you can even do that without a makefile:
# make density.o from a sourcefile
make density.o
Note the built-in rules put the object files next to the source files (unless using VPATH etc etc, more about that in the manual), so you'd call it like
make ../SOURCES_COUNTERFLOW/density.o

Related

Is there a way to define custom implicit GNU Make rules?

I'm often creating png files out of dot (graphviz format) files. The command to do so is the following:
$ dot my_graph.dot -o my_graph.png -Tpng
However, I would like to be able to have a shorter command format like $ make my_graph.dot to automatically generate my png file.
For the moment, I'm using a Makefile in which I've defined the following rule, but the recipe is only available in the directory containing the Makefile
%.eps: %.dot
dot $< -o $# -Teps
Is it possible to define custom implicit GNU Make recipes ? Which would allow the above recipe to be available system-wide
If not, what solution do you use to solve those kind of problem ?
Setup:
Fedora Linux with ZSH/Bash
You could define shell functions in your shell's startup files, e.g.
dotpng()
{
echo dot ${1%.dot}.dot -o ${1%.dot}.png -Tpng;
}
This function can be called like
dotpng my_graph.dot
or
dotpng my_graph
The code ${1%.dot}.dot strips .dot from the file name if present and appends it (again) to allow both my_graph.dot and my_graph as function argument.
Is it possible to define custom implicit GNU Make recipes ?
Not without modifying the source code of GNU Make.
If not, what solution do you use to solve those kind of problem ?
I wouldn't be a fan o modyfying the system globally, but you could do:
Create a file /usr/local/lib/make/myimplicitrules.make with the content
%.eps: %.dot
dot $< -o $# -Teps
Use include /usr/local/lib/make/myimplicitrules.make in your Makefile.
I would rather use a git submodule or similar to share common configuration between projects, rather than depending on global configuration. Depending on global environment will make your program hard to test and non-portable.
I would rather go with a shell function, something along:
mymake() {
make -f <(cat <<'EOF'
%.eps: %.dot
dot $< -o $# -Teps
EOF
) "$#"
}
mymake my_graph.dot
GNU Make lets you specify extra makefiles to read using the MAKEFILES
environment variable. Quoting from info '(make)MAKEFILES Variable':
the default goal is never taken from one of these makefiles (or any
makefile included by them) and it is not an error if the files listed
in 'MAKEFILES' are not found
if you are running 'make' without a specific makefile, a makefile
in 'MAKEFILES' can do useful things to help the built-in implicit
rules work better
As an example, with no makefile in the current directory and the
following .mk files in make's include path (e.g. via
MAKEFLAGS=--include-dir="$HOME"/.local/lib/make/) you can create
subdir gen/ and convert my_graph.dot or dot/my_graph.dot by
running:
MAKEFILES=dot.mk make gen/my_graph.png
To further save some typing it's tempting to add MAKEFILES=dot.mk
to a session environment but defining MAKEFILES in startup files
can make things completely nontransparent. For that reason I prefer
seeing MAKEFILES=… on the command line.
File: dot.mk
include common.mk
genDir ?= gen/
dotDir ?= dot/
dotFlags ?= $(if $(DEBUG),-v)
Tvariant ?= :cairo:cairo
vpath %.dot $(dotDir)
$(genDir)%.png $(genDir)%.svg $(genDir)%.eps : %.dot | $(genDir).
dot $(dotFlags) $< -o $# -T'$(patsubst .%,%,$(suffix $#))$(Tvariant)'
The included common.mk is where you'd store general definitions to
manage directory creation, diagnostics etc., e.g.
.PRECIOUS: %/. ## preempt 'unlink: ...: Is a directory'
%/. : ; $(if $(wildcard $#),,mkdir -p -- $(#D))
References:
?= = := … - info '(make)Reading Makefiles'
vpath - info '(make)Selective Search'
order-only prerequisites (e.g. | $(genDir).) - info '(make)Prerequisite Types'
.PRECIOUS - info '(make)Chained Rules'

don't understand the difference between "gcc -c file.c" and "gcc -o file.c" command

Command :
`gcc -c -Wall hello.c`
Here is the error : while calling ./hello.o
bash: ./hello.o: cannot execute binary file: Exec format error
need help please ..
.o is an object file, not an executable. It's an intermediate step. The -c option just says to make that step. You'll still have to link that object file into an executable.
These are the options you are asking for
-c
Compile or assemble the source files, but do not link. The linking stage simply is not done. The ultimate output is in the form of an object file for each source file.
By default, the object file name for a source file is made by replacing the suffix ‘.c’, ‘.i’, ‘.s’, etc., with ‘.o’.
Unrecognized input files, not requiring compilation or assembly, are ignored.
-o file
Place output in file file. This applies to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code.
If -o is not specified, the default is to put an executable file in a.out, the object file for source.suffix in source.o, its assembler file in source.s, a precompiled header file in source.suffix.gch, and all preprocessed C source on standard output.
Using the first option you will have an object file, not an executable so you cannot execute it

compiling a makefile that has an extenstion .x86 [duplicate]

I have a makefile in a directory of mine which builds scripts with certain environment variables set. What if I want to create another makefile in the same directory with different environment variables set? How should I name the two make files? Does makefile.1 and makefile.2 work? How do I call them?
You can give sensible names to the files like makefile.win and makefile.nix and use them:
make -f makefile.win
make -f makefile.nix
or have a Makefile that contains:
win:
make -f makefile.win
nix:
make -f makefile.nix
and use make win or make nix
You can name makefile whatever you want. I usually name it like somename.mk. To use it later you need to tell make what makefile you want. Use -f option for this:
make -f somename.mk
Actually you can have two set of environment variables in the same make file. for example
COMPILER = gcc
CCFLAGS1 = -g
CCFLAGS2 = -Wall
a: main.c
${COMPILER} ${CCFLAGS1} main.c
b: test.c
${COMPILER} ${CCFLAGS2} test.c
then you can just say make a or make b. Depending on what you want.
Also it is possible with -f flag to call which makefile you want to call.
You can do something like this rather than using multiple makefiles for the same purpose. You can pass the environment or set a flag to the same makefile. For eg:
ifeq ($(ENV),ENV1)
ENV_VAR = THIS
else
ENV_VAR = THAT
endif
default : test
.PHONY : test
test:
#echo $(ENV_VAR)
Then you can simply run the make command with arguments
make ENV=ENV1
I have two makefiles in the same directory. Many of the recipes have identical names and here are two solutions:
1. Prefix in make
proja_hello:
#echo "hello A"
projb_hello:
#echo "hello N"
2. Keep two separate files
Project A has makefile. Type make hello.
Project B has a separate make file called projb.mk. Type bmake hello.
This works since I've added alias bmake ='make -f projb.mk to my .bashrc. Note! This command can be called anywhere but only works where projb.mk exists.
Note! You lose autocompletion of make with the alias and typing make -f projb.mk hello is not better than typing make projb_hello.

How to run Linux shell commands from GNU make file to setup preconditions for a build target

My issue is that in my make file I want to create the directory for all object code before building it and I cannot find a way to do this whithout having it impact the output of make. Also, i want to do it in ONE place and not for each and every object file.
I have tried this:
build: setup exe.i686
setup:
mkdir -p obj
exe.i686: $(OBJS)
#echo 'Building target: $#'
#echo 'Invoking: GCC C++ Linker'
${GCC_LOCATION}/Linux/i686/bin/i686-pc-linux-gnu-g++ $(OBJS) -o "exe.i686" -L...
#echo 'Finished building target: $#'
#echo ' '
where OBJS is all my object code. If I don't run setup first and there is no ./obj directory present the build will fail because of the missing directory when trying to build the object code.
Just to be clear, here is an example of how one object file is built:
./obj/Cell.o: ${CELL_ROOT}/main/cell/Cell/src/Cell.cc
#echo 'Building file: $<'
#echo 'Invoking: GCC C++ Compiler'
$(GCC_C++_BUILD) -MF"$(#:%.o=%.d)" -MT"$(#:%.o=%.d)" -o "$#" "$<"
#echo 'Finished building: $<'
#echo ' '
I don't want to build the object code in the same directory I have my make file.
Now to the actual problem. When I build tarket "build" the first time like this everything works fine:
make build
But if I build it again and there are no updates in my source code (object code is up-to-date) it behaves like this:
[7:37] [user1] [/local/repo/user1/project_x/test/bin] $ make build
mkdir -p obj
[7:37] [user1] [/local/repo/user1/project_x/test/bin] $
In this situation I would have liked make to return the nothing-to-be-done string like this:
[7:37] [user1] [/local/repo/user1/project_x/test/bin] $ make build
make: Nothing to be done for `build'.
[7:41] [user1] [/local/repo/user1/project_x/test/bin] $
This would have been the case if I didn't have to depend on the setup target (which is added to .PHONY). Is the only alternative to do it for each object code file? That would be possible I suppose but I wanted to avoid that if possible as it clutters the make file quite a bit. At least in my opinion.
Thanks
Your target setup is always executed because it has no dependency.
You have two choices:
(1) Make a stamp or use some other mechanism so that there is an actual dependency. The directory itself can be the target but that may incur some wrinkles: see http://www.gnu.org/software/make/manual/html_node/Prerequisite-Types.html for an example.
Modified relevant extract from the linked article:
$(OBJS): | obj
obj:
mkdir $(OBJDIR)
(2) Suppress the output by testing for existence:
setup:
test -d obj || mkdir -p obj
This is similar to the earlier answer, just to make it easier to read:
build: exe.i686
$(OBJS): | obj
obj:
#if [ ! -d obj ]; then mkdir -p obj; fi
exe.i686: $(OBJS)
#echo 'Building target: $#'
...

Make ignores the rule when run for the first time

SO
I can't find out why these lines are not called for the first time I run 'make' but are called the next time:
sb_path = sb
sb_src := $(sb_path)/src
sb_build := $(sb_path)/build
ifndef DO_NOT_GENERATE_COMMIT_INFO
commit_sb: | $(sb_bin)
#$(sb_build)/generate-commit-info $(sb_path)
$(sb_src)/last_git_commit_info.h: | commit_sb ;
endif
I'm just curious because there is no file generate-commit-info file and make crashes when I call it for the second time, but it compiles my program ok for the first try.
I use script on my local machine to copy sources over ssh to another machine and to run compile.sh script there:
...
scp -r $sbfolder/build $sbfolder/Makefile "$buildserver:$root/$curdate"
check_retcode
scp -r $sbfolder/sb/Makefile "$buildserver:$root/$curdate/sb/"
...
ssh $buildserver "$root/compile.sh $curdate $debug"
compile.sh:
# fix Makefile: we don't have git installed here
#DO_NOT_GENERATE_COMMIT_INFO=true
#now we can compile sb
curdir="/home/tmp/kamyshev/sb_new/$1"
cd $curdir
check_retcode
t_path=$curdir
debug=$2
config=RELEASE
if [[ debug -eq 1 ]]; then
config=DEBUG
fi
echo "building sb... CONFIG=$config"
make -j2 CONFIG=$config
check_retcode
As you see DO_NOT_GENERATE_COMMIT_INFO=true is commented out. So I just don't see a reason why the code is not run when I call a make or the script for the first time (either from the remote script or myselft from command line).
Do you have any clues?
UPDATE on Etan Reisner comment:
commit_sb target is checked, it does not exist, so it's rule is being run and it updates last_git_commit_info.h. Thus it forces to update the .h file. It also gives me a .PHONY target commit_sb so I could do it directly by calling make commit_sb.
The generate-commit-info also creates a file in a $(sb_bin) folder.
My another guess is that you are talking about a better way to organize this code.
I can update last_git_commit_info.h directly with a such rule:
commit_sb $(sb_src)/last_git_commit_info.h: FORCE | $(sb_bin)
#$(sb_build)/generate-commit-info $(sb_path)
FORCE:
Thanks to the commenters on my question I've done some additional research: I've tried to make a minimal complete example. And this led me to the answer.
My code generates dependency files (look at -MMD command in SB_CXXFLAGS):
# just example - in real Makefile these are calculated on the fly
sb_deps := file1.d file2.d [...]
# rules with dependances of .o files against .h files
-include $(sb_deps)
SB_CXXFLAGS = $(CXXFLAGS) [...] -MMD
# compile and generate dependency info;
$(sb_obj)/%.o:$(sb_src)/%.cpp
$(CXX) $(SB_CXXFLAGS) $< -o $#
And when I run make for the first time there no *.d files, so no *.cpp depends on last_git_commit_info.h file and the rule is not applied.
On the subsequent runs the dependency rule appears in one of *.d files, the rule is executed and I get the error.
UPDATE: This does not concern the question directly, but this is the better way to write these rules:
ifndef DO_NOT_GENERATE_COMMIT_INFO
commit_sb $(sb_src)/last_git_commit_info.h: FORCE | $(sb_bin)
#$(sb_build)/generate-commit-info $(sb_path)
FORCE:
endif

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