I have some source .cpp files in the same directory, and I want to compile them as object file.
Some of them needs "extra" libraries (same libs for all files) to be linked with and some of them don't, I'd like to write general rules to match the right files, without writing specific rule for each file with extra flags.
More in detail I want to refactor my Makefile so that I don't have to specify different rules for the source files SourceFileOpenCVNeeded.cpp OCVAlsoHere.cpp TheSameForMe.cpp (now they're few, but they could be many more).
Here is what my makefile actually looks like:
CPP_FILES := $(wildcard src/*.cpp)
OBJ_FILES := $(addprefix obj/,$(notdir $(CPP_FILES:.cpp=.o)))
MAIN_SRC := main.cpp
OCV_LIBS := `pkg-config opencv --libs`
OCV_PATH := `pkg-config opencv --cflags`
MY_LIB := launcher
LD_FLAGS := $(MAIN_SRC) -L. -l$(MY_LIB) $(OCV_LIBS)
CC_FLAGS := -c -fPIC
AR_FLAGS := rcs
STATIC_LIB := lib$(MY_LIB).a
CC := g++
EXEC := test
all: lib main
main:
$(CC) $(LD_FLAGS) -o $(EXEC)
lib: $(OBJ_FILES)
ar $(AR_FLAGS) $(STATIC_LIB) $^
obj/SourceFileOpenCVNeeded.o: src/SourceFileOpenCVNeeded.cpp
$(CC) $(OCV_PATH) $(CC_FLAGS) $(OCV_LIBS) -c -o $# $<
obj/OCVAlsoHere.o: src/OCVAlsoHere.cpp
$(CC) $(OCV_PATH) $(CC_FLAGS) $(OCV_LIBS) -c -o $# $<
obj/TheSameForMe.o: src/TheSameForMe.cpp
$(CC) $(OCV_PATH) $(CC_FLAGS) $(OCV_LIBS) -c -o $# $<
obj/%.o: src/%.cpp
$(CC) $(CC_FLAGS) -c -o $# $<
clean:
rm -f $(OBJ_FILES) $(STATIC_LIB) $(EXEC)
PS: any other improvements that can be added to my Makefile?
You might be able to use target-specific variables, e.g. (not tested)
EXTRA_FLAGS=
obj/TheSameForMe.o: EXTRA_FLAGS="$(OCV_PATH) $(OCV_LIBS)"
obj/%.o: src/%.cpp
$(CC) $(CC_FLAGS) $(EXTRA_FLAGS) -c -o $# $<
Related
I'm new on using Makefiles because I've been programming with VS2019 on Windows, solving all my compilation and linking problems.
This is the result:
BUILD_DIR:= ./build
SRC_DIRS := ./src
INCL_DIR := ./includes
CC := /usr/bin/g++ #Compiler used
LVERSION := -std=c++17 #Language Version
CXXFLAGS := -g #Cpp flags
CFLAGS := -Wall #Compiler Flags
LFLAGS := -lstdc++fs #Linker Flags
SRCS := Audio.cpp Song.cpp Visual.cpp VisualSong.cpp
LIBS :=
INCLUDES := $(SRCS:%.cpp=$(INCL_DIR)/%.h)
OBJS := $(SRCS:%.cpp=$(BUILD_DIR)/%.o)
PROG := progName.exe
progName: $(OBJS)
$(CC) $(CFLAGS) $(CXXFLAGS) -o $(INCLUDES) $(PROG) $(OBJS)
$(BUILD_DIR)/%.o: $(INCL_DIR)/%.h $(SRC_DIRS)/%.cpp
$(CC) ${CFLAGS} $(CXXFLAGS) $(LVERSION) ${LFLAGS} -c $^
.PHONY: progName
clean:
/bin/rm -rf build/*.o $(PROG) includes/*.gch
This makefile works until is trying to look on objects file, supposedly created on build directory but, in the end, they're created in Makefile's directory, which is an inconvenient since all what i want is to have separated files for organization purposes.
I know that somehow using implicit rules that are using the dst's directory should do the trick, but i think that I'm missing something on the way...
I'm on a Windows 10 machine with WSL for Ubuntu, but this shouldn't be a problem at all for this problem.
Could anyone explain to me what am I missing?
Look at this rule:
$(BUILD_DIR)/%.o: $(INCL_DIR)/%.h $(SRC_DIRS)/%.cpp
$(CC) ${CFLAGS} $(CXXFLAGS) $(LVERSION) ${LFLAGS} -c $^
Ostensibly it is the rule to build build/foo.o, but the recipe ($(CC)...) actually builds foo.o. There is an easy fix:
$(BUILD_DIR)/%.o: $(INCL_DIR)/%.h $(SRC_DIRS)/%.cpp
$(CC) ${CFLAGS} $(CXXFLAGS) $(LVERSION) ${LFLAGS} -c $^ -o $#
Once that works I suggest you make one further change:
$(BUILD_DIR)/%.o: $(SRC_DIRS)/%.cpp $(INCL_DIR)/%.h
$(CC) ${CFLAGS} $(CXXFLAGS) $(LVERSION) ${LFLAGS} -c $< -o $#
The results for this topic strangely all did not work.
Finally I found a variant that is logical for me and works from the same order.
CC := g++
CFLAGS := -g -Wall
objects = test helloworld
all: $(objects)
$(objects): %: %.cpp
$(CC) $(CFLAGS) -o $# $<
I have tried a lot and probably fail to fully understand the line %: %.cpp.
My interpretation is: I take from every object the dependency which in turn is based on a file which is then traceable to a .cpp file.
My theory is test expects test.o and then test.cpp.
How do I rewrite this to directory?
I have already read some things with wildcards and a pattern replace.
Like
SRC_DIR := src
OBJ_DIR := obj
SRC_FILES := $(wildcard $(SRC_DIR)/*.cpp)
OBJ_FILES := $(patsubst $(SRC_DIR)/%.cpp,$(OBJ_DIR)/%.o,$(SRC_FILES))
LDFLAGS := ...
CPPFLAGS := ...
CXXFLAGS := ...
main.exe: $(OBJ_FILES)
g++ $(LDFLAGS) -o $# $^
$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
g++ $(CPPFLAGS) $(CXXFLAGS) -c -o $# $<
But the behavior was not the expected.
When 2 cpp files were in the folder the result was
g++ -o helloworld.o helloworld.cpp
g++ -o helloworld.o test.cpp
Or vice versa that only the cpp file was always the same.
I have the feeling to miss something extremely.
Update:
The make version is
GNU Make 4.3
Built for aarch64-unknown-linux-android
The Goal
What I would like to achieve is
src/
Test.cpp
Helloworld.cpp
Obj/
Make :
Obj/
Helloworld.out
Test.out
Try this:
CXX := g++
CXXFLAGS := -g -Wall
TARGETS=obj/test.out obj/helloworld.out
all:$(TARGETS)
obj/%.out:src/%.cpp
$(CXX) $(CXXFLAGS) -o $# $^
clean:
rm obj/*
INC_DIR = ./include
SRC_DIR = ./src
OBJ_DIR = ./obj
SRC_FILES = $(wildcard $(SRC_DIR)/*.cpp))
H_FILES = $(wildcard $(INC_DIR)/*.cpp)
OBJ_FILES=$(patsubst $(SRC_DIR)/%.cc,$(OBJ_DIR)/%.o,$(SRC_FILES)
TARGET = PT3
CC = g++
CFLAGS = - fPIC -c -Wall -Werror -pedantic -std=c++11 -Wno-c++11-extensions
CPPFLAGS = $(addprefix -I, $(INC_DIR))
clean:
rm -f $(OBJECTS) $(TARGET)
all: $(TARGET)
$(TARGET): $(OBJECTS)
$(CC) $(CFLAGS) $(CPPFLAGS) -o $# $^
%.o: %.cc
$(CC) $(CFLAGS) $(CPPFLAGS) -o $# -c $<
g++ -shared -fPIC -o libtest.so $(OBJECTS)
main.o: main.cc
$(CC) $(CFLAGS) $(CPPFLAGS) -L/pt3/lib -o maintest main.cc -libtest
this is currently what I have and i know its not syntactically right or remotely working but Im getting stuck on creating the shared library so I dont even know what else wouldnt compile.**
INC_DIR = ./include
SRC_DIR = ./src
SRC_FILES = $(sort $(shell find $(SRC_DIR) -name '*.cc'))
OBJ_FILES = $(SRC_FILES:.cc=.o)
TARGET = PT3
CC = g++
CFLAGS = -fPIC -Wall -Werror -pedantic -std=c++11 -Wno-c++11-extensions
CPPFLAGS = $(addprefix -I, $(INC_DIR))
#clean:
# rm -f $(OBJECTS) $(TARGET)
all: $(TARGET)
$(TARGET): $(OBJ_FILES)
$(CC) $(CFLAGS) $(CPPFLAGS) -o $# $^
%.o: %.cc
$(CC) $(CFLAGS) $(CPPFLAGS) -o $# -c $<
libtest.so: $(OBJ_FILES)
$(CC) -shared -fPIC -o $# $^
maintest: main.o libtest.so
$(CC) $(CFLAGS) $(CPPFLAGS) -L. -o maintest main.o -libtest
this is what i rewrote the code to however Im getting a no input files error, but Im not sure if thats coming from a wrong read / failure to get into the required folders, or due to possibly missing a -o or -c?
Ive worked on the code some more following the suggestions and have come to this:
CXX = g++
CXXFLAGS := -Wall -Werror -pedantic -std=c++11 -Wno-c++11-extensions
SRC_FILES = $(wildcard $(SRC_DIR)/*.cpp)
OBJECTS=$(patsubst $(SRC_DIR)/%.cpp,$(OBJ_DIR)/%.o,$(SRC_FILES))
INC_DIR = include
SRC_DIR = src
OBJ_DIR = obj
TEST_DIR = tests
LIB_DIR = lib
$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
$(CXX) $(CXXFLAGS) -fPIC -Iinclude -o $# -c $<
clean:
rm -f $(OBJECTS) $(TEST_DIR)/main.o
$(LIB_DIR)/libtest.so: $(OBJECTS)
#echo frank
$(CXX) -shared -fPIC -o $# $^
$(TEST_DIR)/main.o: $(TEST_DIR)/main.cc
$(CXX) $(CXXFLAGS) -Iinclude -o $# -c $<
maintest: $(TEST_DIR)/main.o $(LIB_DIR)/libtest.so
$(CXX) $(CXXFLAGS) -Llib -Iinclude -o $# $< -ltest
everything seems to compile fine however when running the maintest program it returns an error saying: error while loading shared libraries: libtest.so: cannot open shared object file: No such file or directory
thanks for the suggestions so far I feel like Im on the verge of actually getting the makefile working as intended
You've already written the recipe for the library (which builds it in the working directory -- we can change that later if you want):
g++ -shared -fPIC -o libtest.so $(OBJECTS)
The next step is to put it into a rule:
libtest.so: $(OBJECTS)
g++ -shared -fPIC -o libtest.so $(OBJECTS)
Then clean it up:
libtest.so: $(OBJECTS)
g++ -shared -fPIC -o $# $^
It looks as if you want the executable to be maintest, so let's write a rule for that:
maintest: main.o libtest.so
$(CC) $(CFLAGS) $(CPPFLAGS) -L. -o maintest main.o -ltest
Give that a try. We can make further adjustments once that much works.
EDIT: I see that there are a few other problems in your makefile. Your variables won't work as written. Do you name your source files "foo.cc" or "foo.cpp"?
EDIT: I can see that we'll have to do this in stages.
Step 1. Try this:
CXX = g++
CXXFLAGS := -Wall -Werror -pedantic -std=c++11 -Wno-c++11-extensions
INC_DIR = include
SRC_DIR = src
OBJ_DIR = obj
$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
$(CXX) $(CXXFLAGS) -Iinclude -o $# -c $<
Try to build one or two object files with this, as in make obj/foo.o.
Step 2. Add a rule for main.o, and test it:
$(OBJ_DIR)/main.o: main.cc
$(CXX) $(CXXFLAGS) -Iinclude -o $# -c $<
Step 3. Add a "do nothing" rule for the library, and verify that it builds all of the objects:
SRC_FILES = $(wildcard $(SRC_DIR)/*.cpp)
OBJECTS=$(patsubst $(SRC_DIR)/%.cpp,$(OBJ_DIR)/%.o,$(SRC_FILES))
libtest.so: $(OBJECTS)
#echo doing nothing
Step 4. Change the library rule to actually build the library:
libtest.so: $(OBJECTS)
$(CXX) -shared -fPIC -o $# $^
Step 5. Add a rule to build the test:
maintest: main.o libtest.so
$(CXX) $(CXXFLAGS) -L. -o $# $< -ltest
This is a part of my makefile :
SRC = ./
DIRS = src libs/maths libs/struct
BIN_DIR = ./bin/
SRC_DIRS= $(foreach dir, $(DIRS), $(addprefix $(SRC), $(dir)))
SRC_TEST= $(sort $(SRC_DIRS))
SRCS = $(foreach msrc, $(SRC_DIRS), $(wildcard $(msrc)/*.c))
DEL_PRE = $(foreach target, $(SRCS), $(notdir $(target)))
ADD_PRE = $(foreach target, $(DEL_PRE), $(addprefix $(BIN_DIR), $(target)))
OBJS = $(ADD_PRE:.c=.o)
.PHONY: all clean re
all: $(EXEC)
$(EXEC): $(OBJS)
$(CC) $(OBJS) -o $# $(LDLIBS)
$(OBJS): $(SRCS)
$(CC) -o $# -c $<
When i use make all, i have in output :
gcc -o bin/main.o -c src/main.c
gcc -o bin/cosin.o -c src/main.c
gcc -o bin/pears.o -c src/main.c
gcc -o bin/outil.o -c src/main.c
gcc -o bin/verif.o -c src/main.c
But i would like to have for each target, it assigned dependency :
gcc -o bin/main.o -c src/main.c
gcc -o bin/cosin.o -c libs/maths/cosin.c
gcc -o bin/pears.o -c libs/maths/pears.c
gcc -o bin/outil.o -c libs/struct/outil.c
gcc -o bin/verif.o -c libs/struct/verif.c
How can i fix it ?
This seems like a very common misconception; I just answered effectively this same question yesterday. I'm not sure where it comes from or how to combat it.
This rule:
$(OBJS): $(SRCS)
$(CC) -o $# -c $<
does not somehow magically combine the contents of the OBJS variable and the SRCS variable to figure out how they match up. The variable references are simply expanded, and the result is this:
bin/main.o bin/cosin.o ... : src/main.c libs/maths/cosin.c ...
$(CC) -o $# -c $<
which is the same as if you'd written this:
bin/main.o : src/main.c libs/maths/cosin.c ...
$(CC) -o $# -c $<
bin/cosin.o : src/main.c libs/maths/cosin.c ...
$(CC) -o $# -c $<
...
Now, you can hopefully see why you compile the same file: in every rule you have the same prerequisites, so $< is always the first one, which is always src/main.c.
There are multiple ways to work this but if you really want to have all the source files from different directories compiled into object files in the same directory your job is harder, because there's no common pattern that will match them all. In this case the simplest thing to do is use VPATH for directory search: replace the above rule with this:
$(BIN_DIR)/%.o : %.c
$(CC) -o $# -c $<
then tell make how to find your source files, like this:
VPATH := $(sort $(dir $(SRCS))
Be aware this method can't be used for any source files that are themselves generated output that make is expected to create.
I have the following Makefile:
CXX = g++
CXXFLAGS = -Wall -g
SOURCES := divisor.cpp multiplier.cpp
OBJECTS := ${SOURCES:.cpp=.o}
%.o: %.cpp
$(CXX) -c $(CXXFLAGS) $< -o $#
%: %.o $(OBJECTS)
$(CXX) $(CXXFLAGS) $#.o -o $#.out
$(OBJECTS): %.o: %.cpp
$(CXX) -c $(CXXFLAGS) $< -o $#
clean:
rm -f *.o
What I want this make file is the following:
If I add a source file called 123.cpp to the working directory, I want it to generate its object file and then link the compiled sources specified in $(SOURCES), this means:
g++ -c -Wall -g 123.cpp
g++ multipler.o divisor.o 123.o -o 123
If multiplier.cpp or divisor.cpp has to be generated or updated, I want make to do it.
But I'm failing, because divisor.o and multiplier.o are not automatically generated
How may I achieve this?
Edit
Just to clarify, there are two types of source code files in the working directory: divisor.cpp, multipler.cpp is one type, and any other file, say, 123.cpp is the other type. In a sense, divisor.cpp and multiplier.cpp are requisites to the other source files.
I want to automate the process of compiling the prerequisites and link them when compiling the other files
g++ -c multiplier.cpp
g++ -c divisor.cpp
g++ -c -Wall -g 123.cpp
g++ multipler.o divisor.o 123.o -o 123
Use the wildcard function:
SOURCES := $(wildcard *.cpp)
Then, you can remove your "special" source files:
SPECIAL_SOURCES := divisor.cpp multiplier.cpp
SOURCES := $(filter-out $(SPECIAL_SOURCES),$(SOURCES))
And change your rules to build the stuff you actually want:
$(SPECIAL_OBJECTS) := $(SPECIAL_SOURCES:.cpp=.o)
$(BINARIES) := $(patsubst .cpp,,$(SOURCES))
$(SPECIAL_OBJECTS) : %.o : %.cpp
$(CXX) $(CXXFLAGS) -c -o $# $^
$(BINARIES) : % : %.cpp $(SPECIAL_OBJECTS)
$(CXX) $(CXXFLAGS) -o $# $^