I know that makefile is used for a project where files are related. But I want to use it in a different way.
Since I always write lots of test files, I need to type a bunch of flags every time I compile them, that's so troublesome. I just want to write a makefile that compiles all source files into executables with their corresponding names - like a.c to a and b.c to b, etc. so that I can get executables by simply typing make instead of the whole gcc ...
Is there any simple way to do it?
Make has a built in implicit rule like this:
% : %.c
$(CC) -o $# $(CFLAGS) $<
$(CFLAGS) would contain all your options.
Then, doing
make foo
Would try to produce foo from foo.c (if it existed).
To be able to compile all of them in one go, add another rule:
all: $(patsubst %.c,%,$(wildcard *.c))
This new rule, called 'all', has the list of your executables as its prerequisite. The wildcard function lists all .c files in the directory, and the patsubst removes the .c from each of them, leaving a list of the executables that would be produced from each .c file.
So doing
make all
causes it to try to compile each .c file into the corresponding executable.
Alright understood. I'm not too sure if you'll understand the syntax. I'll try to explain as much as I can.
you'll make a file called Makefile no extensions.
DIR=$(HOME)/../"Your directory"
all: "Whatever driver you may have"
purify: purify g++ -o "Your file" -Wall -pedantic -g "objective file .o extension"
# Makes clean file
clean:
rm -f *.o "Drivers"
new:
make clean
make
make has built in implicit rules to do that. Just type make a or make b or make a b or whatever you want. Add and export an environment variable called CFLAGS if you want to add any special options.
Related
Im fairly new to makefiles. I want to compile multiple executables through my makefile, and it was to my understanding that having a target with multiple entries would run the recipe for that target through all entries. My example is:
$(EXE): $(OBJS)
g++ -o $# $< -L$(LIBPATH) -lOSApi -lrt -lpthread
My EXE variable contains all files that should be created, something like: prog1 prog2 and so on. My OBJS contains prog1.o prog2.o and so on.
When running make i create all .o files perfectly, but i only create one executable. I have tried replacing $# with $(EXE) and such, but no luck so far.
Any help would be appreciated.
EDIT:
I found the solution through MadScientist, who suggested to add an all target, and then changing my executable target to:
$(EXE): % : %.o
g++ -o $# $< -L$(LIBPATH) -lOSApi -lrt -lpthread
.PHONY: all clean
all: $(EXE)
Which to my understanding makes every target in my EXE target dependant on its corresponding .o file.
It would help greatly if you provided a full (small) sample. In the question you don't show us what the definition of EXE or OBJS is which makes it hard to say exactly.
Also, please be sure to format your question correctly.
By default make only builds the FIRST target in the makefile. It doesn't build ALL the targets in the makefile. So, if EXE contains multiple targets and the first rule in your makefile is $(EXE) : ... then only the first target in that list will be built.
You should add a new target before the above, saying that you want the default to build all the exe's. You can call it anything you like but the convention is to call it all:
all: $(EXES)
(you can also add a .PHONY: all for safety). Now the first target in the makefile is all, and as prerequisites it will build all the targets in the EXES variable.
I have the following source files:
% ls
data_lexicon.c data_lexicon.h lex.l makefile
And the following makefile:
% cat makefile
CC = cc
CFLAGS = -Wall -std=c89
LDFLAGS = -ll
OBJFILES = lex.o data_lexicon.o
TARGET = lexical_analyzer_1
all: $(TARGET) lex.c
lex.c: lex.l data_lexicon.h
lex -olex.c lex.l
$(TARGET): $(OBJFILES)
$(CC) $(CFLAGS) -o $(TARGET) $(OBJFILES) $(LDFLAGS)
clean:
rm -f $(OBJFILES) lex.c $(TARGET)
If I do make all I get:
% ls
data_lexicon.c data_lexicon.o lex.l
lexical_analyzer_1 data_lexicon.h lex.c
lex.o makefile
So far so good.
However, I would like to move the source files (data_lexicon.c, data_lexicon.h, lex.l) to a folder src and generate the intermediate files (data_lexicon.o lex.c, lex.o) into a obj folder.
I create both folders but I do not understand how the makefile file shall be configured.
I am using FreeBSD make, so the more portable the solution given the better.
However, I would like to move the source files (data_lexicon.c,
data_lexicon.h, lex.l) to a folder src and generate the intermediate
files (data_lexicon.o lex.c, lex.o) into a obj folder.
It never ceases to amaze me how people insist on making extra work for themselves. You can certainly do what you describe, but it will require writing explicit rules for the object files.
First of all, however, you need to understand that make itself doesn't really know anything about directories. (Traditional make doesn't, anyway. GNU make and perhaps others know a little about them.) That is, it doesn't have any sense of varying directories against which it resolves file names. Rather, every target name is resolved against make's working directory. If you want to refer to something in a subdirectory, then you must say so. To begin with:
OBJFILES = obj/lex.o obj/data_lexicon.o
Similar goes for target and prerequisite names in rules:
obj/lex.c: src/lex.l src/data_lexicon.h
lex -o$# src/lex.l
That's also one reason to favor make's automatic variables, such as the $# in the above rule representing the name of the target being built.
Your makefile presently relies on make's built-in rule for building object files from corresponding C source files, but "corresponding" means target and prerequisite names are identical, including any path components, except for the suffixes (.c vs .o). You will no longer have that correspondence for data_lexicon.o, so you will need to write an explicit rule for it building it. This part is left as an exercise.
My project includes .c and .s (asm) files. I compile both types with 'gcc' and put output .o files to separate directory './bin'. To do that I'm using single makefile rule like this
bin/%.o: %.[cs]
$(CC) $(CFLAGS) -o $# -c $<
(As far as I understand, using square brackets wildcard in such context is a little bit unconventional, but it's working and it looks neat, so...)
The other day I decided to move some of my .c files to dedicated directory './common', so I added
vpath %.c common
at the beginning of the makefile. And now each time I try to 'make', it stops and throws an error on a file I had moved. For example, for 'common/foo.c' I get
"*** No rule to make target bin/foo.o, needed by..."
as if I haven't specified 'vpath'. But when I modify the rule to compile only .c files
bin/%.o: %.c
... ...
magically it starts to operate properly again and checks './common' for sources.
Looks like 'vpath' mechanism and wildcards can not work together, but I'm still new to 'make' and eager to learn what's the exact reason of such behavior. Any ideas anyone? Thanks in advance.
(Tested with make–3.81 and make–4.1.)
UPD: Having all the files and 'bin' directory reside on the same level like so
|-bin/
|-foo.c
|-bar.s
|-baz.c
|-Makefile
here's MWE
ROOTS = foo.o bar.o
OBJS = baz.o
SS = $(addprefix bin/,$(ROOTS) $(OBJS))
all: ff.out
ff.out: $(SS)
ld -o $# $^
bin/%.o: %.[cs]
gcc -o $# -c $<
Now if I move, say, 'foo.c' to separate directory and specify 'vpath', build stops with "No rule to make target bin/foo.o, needed by ff.out".
I suggest careful reading of How Not to Use VPATH as you seem to be at Step Three of that by having the OBJDIR in some places but not others.
To be explict, using a static pattern rule doesn't get you away from needing either at least one rule per source directory, or at least one make invocation per source directory. So, the simple answer is add a new rule for the new common/ directory that's the same as the other one:
bin/%.o: common/%.[cs]
gcc -o $# -c $<
There are lots of more comprehensive, but complex, answers, see the followon article for some of them.
For simple projects, there is no reason not to just track what directories you have in your main Makefile by adding extra rules. Also, there's a reasonable case for not having that bin/ dir and splitting .o and .out locations. Distributors and others expect to be able to control where files are created running from a seperate directory anyway.
I've thrown up a git repo with branches based on your cut down example that may clarify things.
I'm trying to create a makefile for a suite of programs that I am working on. The programs are all written in fortran and the source files are contained in different directories. I can't seem how to figure out how to get things to work. My current sumfile is
#Compiler and compiler flag variables
FCOMP=/usr/local/bin/gfortran
F_FLAGS=-O2 -fbounds-check -Wall
F_FLAGSDB=-g -fbounds-check -Wall
#paths to libraries
COMMON_LIB=/usr/local/lib/libspc_common.a
SPICE_LIB=/usr/local/lib/spicelib.a
# Paths to directories
BIN_DIR=BIN
# Get file names of component source files
#get names of files in src1
FORT_FILES=$(wildcard ./SRC1/*.f)
#get names of files in src2
FORTFILES+=$(wildcard ./SRC2/*.f)
#get names of files in src3
FORTFILES+=$(wildcard ./SRC3/*.f)
#get file names for output
EXE_FILES=$(addprefix $(BIN_DIR),$(notdir $(patsubst %.f, % , $(FORTFILES))))
# make commands
# Set the default option to compile the library with optimization
default: all
# create all command
all: $(EXE_FILES)
#echo toolkit has been built with optimization
#If compiling for debugging replace the compiler flags to remove optimization and add debugging
debug: F_FLAGS=$(F_FLAGSDB)
#Run compiler with debugging flags
debug: $(EXE_FILES)
#echo toolkit has been built with debugging
# Compile all of the source files into executables
$(EXE_FILES): % : %.f
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $(BIN_DIR)/$#
# install the library in /usr/local/lib
install:
cp -p $(BIN_DIR)* /usr/local/bin/toolkit/
# remove executable files for a clean build
clean:
rm $(BIN_DIR)*
The problem I am running into is that I get the following error when I try to run make:
make: *** No rule to make target `Display.f', needed by `Display'. Stop.
which I am assuming is because I have lost the directory that the source file comes from. Can someone help me here? I am totally stuck and don't know how to proceed.
In addition (this is more a general question about make), is there a way to tell make to recompile everything if the COMMON_LIB changes?
Thanks for your help!
Suppose your source files are
SRC1/alpha.f
SRC1/beta.f
SRC2/gamma.f
SRC3/delta.f
1) There is a flaw here:
EXE_FILES=$(addprefix $(BIN_DIR),$(notdir $(patsubst %.f, % , $(FORTFILES))))
This will produce
BINalpha BINbeta BINgamma BINdelta
when I think you intended
BIN/alpha BIN/beta BIN/gamma BIN/delta
A simple fix:
EXE_FILES=$(addprefix $(BIN_DIR)/,$(notdir $(patsubst %.f, % , $(FORTFILES))))
2) Now look at the static pattern rule:
$(EXE_FILES): % : %.f
...
So to build BIN/alpha, Make must first find BIN/alpha.f, which doesn't exist. To make it look for alpha.f, do this:
$(EXE_FILES): $(BIN_DIR)/% : %.f
...
3) How to find the sources?
You could do some delicate coding to help Make remember where it found alpha.f, but there's no need when we can use the vpath directive:
vpath %.f SRC1 SRC2 SRC3
4) One last look at that rule:
This command:
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $(BIN_DIR)/$#
Will produce e.g. BIN/BIN/alpha, which is silly. A non-PHONY Make rule should produce a file whose name is the target of the rule. It prevents a lot of trouble.
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $#
A few further refinements may be possible, once you have this working perfectly.
A common type of makefile has a line like this:
OBJS=something.o other.o third.o progname.o
progname: $(OBJS)
Then you would run make progname. But GNU Make can also generate the list of o-files itself from all the c-files it sees in the current directory. How is this done?
Basically, I want to be able to add C files to the directory without having to change the makefile.
(Is it for instance through some shell-magic, or is there is a built-in function for this?)
It can also be done like this:
SRCS = $(wildcard *.c)
OBJS = $(SRCS:.c=.o)
progname: $(OBJS)
Which works just fine if the object file with main() in it is "progname.o".
To view all the defined rules (include the implicit ones), issue make -p.
However the fact that make knows how to generate object files from source files, does not mean that it should do this. Make will try to do the bare minimum in order to satisfy the target you ask it to build.
If you want make to compile all the sources into object in the current directory you will need a rule that will depend on all the objects, e.g.:
all: $(patsubst %.c,%.o,$(wildcard *.c))
You can expand a shell command to give you a list of files. You can also use implicit rules.
It can be done like this:
$(ODIR)/%.o: %.cpp
$(CC) -c $(CFLAGS) -o $# $<
make generates .o file names from .cpp file names it found in the current directory.