I am pretty new to Makefiles, so my question might be silly. It would be the following: Can I pass another argument to make so that I can do stuff with this additional argument?
More specifically, if possible, I would want to use this to compile any single C source code into its executable using a Makefile.
For example, if I have two files foo.c and bar.c, I would want to be able to compile them using the same recipe, therefore doing something similar to make compile foo.c or make compile bar.c that compiles them into the foo or bar executables, respectively.
If it is not possible, is there an alternative I can do for simple C programs? It would be useful to save time (not updating the Makefile or not writing gcc -o name name.c every time I want to compile a C file I just created).
Thank you in advance for your patience and time.
If you are dealing with single main file applications, a bash script sounds much simpler, build.sh:
#!/bin/bash
SOURCE=$1
BIN=${SOURCE%.c}
if [[ -z "$SOURCE" || ! -s "$SOURCE" ]]; then
echo "SOURCE is empty"
exit 1
fi
gcc -o "$BIN" "$SOURCE"
and then invoke it like this:
./build.sh foo.c
./build.sh bar.c
I use the makefile below for this. 'make' or 'make all' compiles each .c (eg eg.c) file in the directory to an executable in the same directory (eg eg). 'make eg' compiles just eg.c to eg . There's nothing special about the compiler flags -- CFLAGS -- or linker flags -- LFLAGS -- they're just what I habitually use.
CC = gcc
CFLAGS = -std=gnu11 -Wall -Wextra
LFLAGS = -lm -lrt
OPATH = ./
PROGS += $(patsubst %.c,$(OPATH)%,$(wildcard *.c))
all: $(PROGS)
$(OPATH)% : %.c ; $(CC) $(CFLAGS) $< -o $# $(LFLAGS)
clean:
\rm -f $(PROGS)
Make has built-in rules that knows how to compile a source file into an executable.
So, you don't even have to write a makefile at all (unless you want to use special compiler options). This will work:
$ ls
bar.c foo.c
$ make foo
cc -o foo foo.c
$ make bar
cc -o bar bar.c
If you want to modify the compiler operations, add a makefile that sets the appropriate built-in variables:
$ ls
bar.c foo.c Makefile
$ cat Makefile
CC = gcc
CFLAGS = -O2 -g
$ make foo
gcc -O2 -g -o foo foo.c
$ make bar
gcc -O2 -g -o bar bar.c
how about using this:
================== makefile =====================
CC=gcc
CCFLAGS=-ansi -pedantic -Wall
all : clean foo bar
foo : foo.c
$(CC) $(CCFLAGS) foo.c -o foo
bar : bar.c
$(CC) $(CCFLAGS) bar.c -o bar
clean :
rm -f *.o *.*~ foo bar
====================== end makefile ======================
invoking make as make will run the default target (all in this case) removing all intermediate files and output files and then rebuilding foo and bar
invoking make as make foo will only run the rule for making foo.
invoking make as make bar will only run the rule for making bar.
invoking make as make clean will only run the rule for cleaning the project directory -- removing all intermediate and output files.
Related
I have the following Makefile.
objects = foo.o bar.o all.o -- line 1
all: $(objects)
# These files compile via implicit rules
foo.o: foo.c
bar.o: bar.c
all.o: all.c
all.c:
echo "int main() { return 0; }" > all.c
%.c:
touch $#
clean:
rm -f *.c *.o all
When i run make, i get the below output.
echo "int main() { return 0; }" > all.c
cc -c -o all.o all.c
touch foo.c
cc -c -o foo.o foo.c
touch bar.c
cc -c -o bar.o bar.c
cc all.o foo.o bar.o -o all
Question:
Line 1 of the Makefile shows foo.o is the first dependency. So why all.o which depends on all.c are executed first?
You are confusing things by having the file all.c (and object file all.o) and the target all. Conventionally, the all target is a pseudo-target (.PHONY in GNU Make) for 'all the things that are (normally) built by this makefile. This isn't enforced — it is merely convention.
However, here, make is trying to use all.c to build a program all. And it knows it can build all by compiling all.c, so it generates that first.
You could clarify things by either using any.c instead of all.c and building any.o and program any, and having the all: target read:
all: any
That would build the program any
[Files in my directory][1]
Need help compiling in a make file.
So I have this link list assignment i'm doing and the directions were.
stringlist.h is supposed to contain the node and the function prototypes
stringlist.c is supposed to have the functions completed that are defined in stringlist.h. BUT stringlist.c is not supposed to contain main at all. Then, namelist.c is supposed to contain main and just have the I/O and its just supposed to call the command functions that are in stringlist.c.
So to compile this we are supposed to create a make file. Whenever I try to I get an error because main doesn't exit in one of the c files. Throughout the term we compiled code like this "gcc -std=gnu99 -m32 -Wall -g -o file file.c"
But it doesn't work.
How would I create the make file? Been spending hours and can't figure it out.
As stated by Jonathan Leffler, the sample Makefile I provided had a few bad ideas. Here's an improvement:
# compiler:
CC = gcc
# compiler flags:
CFLAGS = -g -Wall
# the build target executable:
TARGET = executable
# object files to build:
OBJ = namelist.o stringlist.o
all: $(TARGET)
$(TARGET): $(OBJ)
$(CC) $(CFLAGS) -o $(TARGET) $(OBJ)
Try this:
OBJ := namelist.c stringlist.c
GCC := gcc -g
CFLAGS := -std=gnu99 -m32 -Wall
compile: $(OBJ)
$(GCC) $(CFLAGS) $(OBJ) -o executable
When I do practice , I have a practice path.
Under this path , I have an Include path named myInclude (I have some useful function is this folder and I always use it.)
And a code path named symbol_try.I always make add new folder (with a c file and main function in it) in symbol_try and compile it.
Each time I have to compile it by gcc in terminal .Its a boring work , so I write a Makefile.
Here is an example:
the main Makefile in practice path:
FOBJS=
include myInclude/Rule.mk
include symbol_try/codeList_13.1/Rule.mk
symbol:$(FOBJS) <==What exactly I what . A executable file.
gcc -o symbol $(FOBJS) -pthread -lpthread
subsystem:
cd myInclude/ && $(MAKE)
cd symbol_try/codeList_13.1/ &&$(MAKE)
clean:
rm -rf symbol
In the myInclude/Rule.mk
FOBJS+=myInclude/otherFunction.o myInclude/error.o \
myInclude/unit.o myInclude/unitTest.o\
In the symbol_try/codeList_13.1/Rule.mk
FOBJS+=symbol_try/codeList_13.1/codeList_13.1.o
In myInclude/Makefile:
OBJS=otherFunction.o error.o unit.o unitTest.o
ALL:$(OBJS)
.PHONY:ALL
$(OBJS):%.o:%.c
gcc -c $< -o $#
clean :
otherFunction.o error.o unit.o
In symbol_try/codeList_13.1/Makefile:
codeList_13.1.o:codeList_13.1.c
gcc -c codeList_13.1.c
Well.That can work. But as you see , I have to write a Rule.mk(to initialize the FOBJS) and a Makefile for each folder.
I am new for make , I want find a way more concise , witch I only need write one Makefile for each folder and a main Makefile.No Rule.mk any more.
PS: I always change the code in myInclude ,so I don't want to build it a library.
Thanks for any help.
Here's one way you can do it with just one Makefile:
CC = gcc
CPPFLAGS += -I myInclude/ (1)
CFLAGS += -std=c99 -Wall (2)
VPATH = myInclude/ \ (3)
symbol_try/codeList_13.1/
symbol: otherFunction.o error.o unit.o unitTest.o codeList_13.1.o (4)
$(CC) -o $# $^ (5)
.PHONY : clean
clean:
rm -f symbol *.o
Note that make knows how to build C files and has some standard macros: CC, CPPFLGAS, CFLAGS
Add the include paths of your headers. You presumably have some headers for the individual object files in the myInclude directory.
Put the compiler flags here.
Add the paths to the source files you want to build.
List the object files that the executable depends upon
As there is no file called symbol.c you need to tell make how to create symbol.o with a rule. $# means the target ('symbol', here), and $^ means all of the prerequisites (the object files listed).
Here's a list of all of the files in my test directories for this:
$ find . -type f
.
./Makefile
./myInclude/error.c
./myInclude/header.h
./myInclude/otherFunction.c
./myInclude/unit.c
./myInclude/unitTest.c
./symbol_try/codeList_13.1/codeList_13.1.c
And the build output:
$ make
gcc -std=c99 -Wall -I myInclude/ -c -o otherFunction.o myInclude/otherFunction.c
gcc -std=c99 -Wall -I myInclude/ -c -o error.o myInclude/error.c
gcc -std=c99 -Wall -I myInclude/ -c -o unit.o myInclude/unit.c
gcc -std=c99 -Wall -I myInclude/ -c -o unitTest.o myInclude/unitTest.c
gcc -std=c99 -Wall -I myInclude/ -c -o codeList_13.1.o symbol_try/codeList_13.1/codeList_13.1.c
gcc -o symbol otherFunction.o error.o unit.o unitTest.o codeList_13.1.o
Why don't you create a library from the objects in myInclude and do the linking in the Makefile in your code path (symbol_try/codeList_13.1). The latter is better anyway because the needed libraries (-pthread -lpthread in your case) might change as well for some other code.
The main Makefile now would have got nothing to do but call make in all needed subdirectories.
In each folder have a makefile with
SOURCES=sample.c sampletest.c
OBJECTS=$(SOURCES:%.c=$(OBJDIR)/%.o)
all: $(OBJECTS)
$(OBJDIR)/%.o: %.c
$(CC) $(CFLAGS) -o $# $<
In the root directory of a project, create a makefile with a rule to compile every sub-folder like the below.
Dirs= path-to-rootdir
objs:
set -e ; \
for i in $(Dirs) ; do \
$(MAKE) CC="$(CC)" CFLAGS="$(CFLAGS_MODULE)" LDFLAGS="$(LDFLAGS)" OBJDIR="$(OBJDIR)" -C $$i; \
done
And then you could use it build the executable by adding a rule
EXE: objs
$(CC) -L./Path1 $(LIB_PATH) -llib1 -o $(EXE_NAME) $(wildcard $(OBJDIR)/*.o)
Hope this helps!!!
I am trying to write a makefile which uses macros to create multiple executables from multiple files at once. I tried searching through previously answered questions but, because I am fairly new to programming in C as well as working with gcc, I was not able to find an answer to my question.
Here is what I have so far:
CC=gcc
CFLAGS=-I.
OBJ = ex1.c ex3.c
EXECUTABLE = ex1 ex3
$(EXECUTABLE): $(OBJ)
gcc -o $# $^ $(CFLAGS)
clean:
rm -f $(EXECUTABLE)
I would like the line
$(EXECUTABLE): $(OBJ)
to create executables ex1 and ex3 from files ex1.c ex3.c respectively.
For this particular case, where each executable has a single source file with .c extension, all you need is a one line Makefile:
all: ex1 ex3
The built-in default rules for make then work already:
$ make
cc -O2 -pipe ex1.c -o ex1
cc -O2 -pipe ex3.c -o ex3
Behind the scene, make is using the POSIXly mandated built-in single suffix rule
.c:
$(CC) $(CFLAGS) $(LDFLAGS) -o $# $<
Vary the command to your liking with make CC=gcc CFLAGS=-O2 LDFLAGS=-s and similar.
Trivia of the day: in fact, if you are willing to name the targets when invoking make, you can use an empty or even run without any Makefile:
$ make -f /dev/null CC=gcc CFLAGS=-O2 LDFLAGS=-s ex1 ex3
gcc -O2 -s ex1.c -o ex1
gcc -O2 -s ex3.c -o ex3
$ rm -f Makefile ex1 ex3
$ make CC=gcc CFLAGS=-O2 LDFLAGS=-s ex1 ex3
gcc -O2 -s ex1.c -o ex1
gcc -O2 -s ex3.c -o ex3
Make magic!
As a rule of thumb, don't reinvent the wheel (or rules), use the rules that are already there. It simplifies your and make's life a lot. This makes for small and sexy makefiles to impress the ladies with :-)
Some suggestions (assuming you use GNU make, not something else)
First, run once make -p, you'll understand what builtin rules make is knowing. Look in particular for COMPILE.c and LINK.c
Then, I suggest
CFLAGS= -g -Wall -I.
(because you really want -g for debugging, and -Wall to get most warnings)
And you probably don't need
$(EXECUTABLE): $(OBJ)
gcc -o $# $^ $(CFLAGS)
However, I suggest adding before most other rules
.PHONY: all clean
all: $(EXECUTABLES)
Actually, I would code your Makefile (for GNU make!) as follow
# file Makefile
CC= gcc
RM= rm -vf
CFLAGS= -Wall -g
CPPFLAGS= -I.
SRCFILES= ex1.c ex2.c ## or perhaps $(wildcard *.c)
OBJFILES= $(patsubst %.c, %.o, $(SRCFILES))
PROGFILES= $(patsubst %.c, %, $(SRCFILES))
.PHONY: all clean
all: $(PROGFILES)
clean:
$(RM) $(OBJFILES) $(PROGFILES) *~
## eof Makefile
Remember that tab is a significant character in Makefile-s (action part of rules). In this answer, lines starting with four spaces at least should really start with a tab character.
Once everything is debugged consider running make clean to clean everything, and then make -j CFLAGS=-O2 all to compile in parallel everything with optimizations.
At last, I recommend using remake and running remake -x to debug complex Makefile-s
Of course, I'm supposing that your directory has only single-file programs.
BTW, there are other build automation tools. Perhaps you might consider using omake or ninja. For building large programs (millions of source code lines) consider also automake, ccache, cmake, icecream. In some cases, consider generating some C code with GPP, GNU bison, SWIG, etc... or using your own Python or Guile script (or C meta-program). See also this draft report.
Don't forget to use a version control system like git for your source files. It is also time to learn such a tool.
The following answer includes multiple executable such as initiate, process1, process2, ..., process4.
LOCAL_INCLUDE=./
all: clean process_first process_second init
process_first:
gcc -g -o process1 -I$(LOCAL_INCLUDE) process1.c -lzmq -L. -L./.
gcc -g -o process2 -I$(LOCAL_INCLUDE) process2.c -lzmq -L. -L./.
process_second:
gcc -g -o process3 -I$(LOCAL_INCLUDE) process3.c -lzmq -L. -L./.
gcc -g -o process4 -I$(LOCAL_INCLUDE) process4.c -lzmq -L. -L./.
init:
gcc -g -o initiate -I$(LOCAL_INCLUDE) initiate.c -lzmq -lconfig -lpthread -L. -L./. -ldl -lrt
clean:
rm -rf init_manager.o init_manager
rm -rf process1 process2 process3 process4
NOTE: It is a good practice to clean and touch all the executable files before making them again.
You're close, but you need a pattern rule:
$(EXECUTABLE): % : %.c
And then a default rule to make it build both:
all: $(EXECUTABLE)
When we are compiling a C program the output is stored in a.out. How can we redirect the compiled output to another file?
Most C compilers provide an option for this, such as the -o option for gcc and some others:
gcc -o gentext gentext.c
cc -o mainprog -Llib -lmymath firstbit.c secondbit.o
xlc -o coredump coredump.c
-ofilename will make filename instead of a.out.
According to the manual:
-o <file> Place the output into <file>
In Unix, where C originated from, C programs are usually compiled module-by-module, and then the compiled modules are linked into an executable. For a project that consists of modules foo.c and bar.c, the commands would be like this:
cc -c foo.c
cc -c bar.c
cc -o myprog foo.o bar.o
(With -c, the output filename becomes the source file with the suffix replaced with .o.)
This allows you to also re-compile only those modules that have changed, which can be a big time saver for big programs, but can also become pretty tricky. (This part is usually automated using make.)
For a single-module program there's not really any point in first compiling to a .o file, and then linking, so a single command suffices:
cc -o foo foo.c
For single-module programs, it is customary to call the resulting executable program the same as the C source file without the .c suffix. For multi-module programs, there is no hard custom on whether the output is named after the file with the main function or not, so you're free to invent whatever strikes your fancy.
With the -o option.
gcc main.c -o myCoolExecutable.o
This is ok if your program consists of a single file. If you have more files I suggest using make: create a Makefile and then run the command make.
A Makefile is a file containing some rules for compilation.
An example can be the following (# means the line is a comment):
CXX = gcc
#CXXFLAGS = -std=c++11
#INC_PATH = ...
#LIBS = ...
SOURCEDIR := yourSourceFolder
SOURCES := $(wildcard $(SOURCEDIR)/*.c)
OBJDIR=$(SOURCEDIR)/obj
OBJECTS := $(patsubst $(SOURCEDIR)/%.c,$(OBJDIR)/%.o, $(SOURCES))
DEPENDS := $(patsubst $(SOURCEDIR)/%.c,$(OBJDIR)/%.d, $(SOURCES))
# ADD MORE WARNINGS!
WARNING := -Wall -Wextra
# .PHONY means these rules get executed even if
# files of those names exist.
.PHONY: all clean
# The first rule is the default, ie. "make",
# "make all" and "make parking" mean the same
all: yourExecutableName
clean:
$(RM) $(OBJECTS) $(DEPENDS) yourExecutableName
# Linking the executable from the object files
# $^ # "src.c src.h" (all prerequisites)
yourExecutableName: $(OBJECTS)
$(CXX) $(WARNING) $^ -o $#
#$(CXX) $(WARNING) $(CXXFLAGS) $(INC_PATH) $^ -o $# $(LIBS)
-include $(DEPENDS)
$(OBJDIR):
mkdir -p $(OBJDIR)
$(OBJDIR)/%.o: $(SOURCEDIR)/%.c Makefile | $(OBJDIR)
$(CXX) $(WARNING) -MMD -MP -c $< -o $#
Shortly CXX variable defines your compiler (gcc, g++), with CXXFLAGS you can define flags for your compilation (i.e. -std=c++11). Then you can include and define custom (INC_PATH and LIBS: not set in the example). With SOURCEDIR you can specify your source code directory (where *.c files are).Then SOURCES is basically telling that the source files for the compilation are all the files having extension *.c.
The Makefile contains a set of rules whose structure is the following:
output: inputs
commandToExecute
The rule to generate your executable file is
yourExecutableName: $(OBJECTS)
$(CXX) $(WARNING) $^ -o $#
which is equivalent to gcc -Wall -Wextra $(OBJECTS) -o yourExecutableName.
$(OBJECTS) are the object file resulting from the compilation. When the above rule is executed, if they are not found make will continue scanning the file to find a rule to generate them. In this case the rule to generate these files is:
$(OBJDIR)/%.o: $(SOURCEDIR)/%.c Makefile | $(OBJDIR)
$(CXX) $(WARNING) -MMD -MP -c $< -o $#
If further information is needed let me know.
If foo will be your executable and bar.c is your source file then the command is:
gcc -o foo bar.c
Compile using:
cc -o <opfilename> <filename.c>
Execute using:
./<opfilename>
gcc filename.c -o outputfile
This command will directly create an outputfile.exe OR outputfile.out according to operating system. In place of filename.c OR outputfile we can enter path, as shown below.
gcc ./home/user/filename.c -o ./home/outputfile
The format of giving the Name of .exe file according to the User Choice in C Language
step 1 :- Run the gcc (or the compiler you have) in the below format on the Terminal
gcc -o put_your_name_you_want_to_give (space) your_file_name_you_want_to_execute
NB:- If you are Running "Vs Code" Use the 'Tab' key for the Auto completion.
step 2 :- Write down the name of the program in format
.\the_name_you_have_given.exe
you are done!
Assuming you are in ubuntu
step-1: run gcc with these commands to compile filename.c
gcc filename.c -o filename.out
filename.out will be created, (it might or might not be shown where the other files are stored)
step-2: execute the filename.out by
./filename.out
step-3: wait for the output
thats it , you are done