I'm trying to practice using Makefiles for a very simple program. The program files are:
main.cpp
other.cpp
other.h
I want the final executable to be Prog.
What happens when I run this is I get a main.o and other.o but no Prog.
What am I missing here?
## file Makefile
CXXOBJECTS= %.o
CXX= g++
CXXSOURCES= main.cpp other.cpp
CXXFLAGS= -std=c++11 -O2
Prog : main.o other.o
main.o : main.cpp
other.o : other.cpp other.h
## eof Makefile
You're almost there. You have the following:
Prog: main.o other.o ## these are your dependencies
g++ main.o other.o -o Prog
This should give you an executable called Prog. Though actually, a better makefile would be this:
CXXOBJECTS= %.o
CXX= g++
CXXSOURCES= main.cpp other.cpp
CXXFLAGS= -std=c++11 -O2
Prog: main.o other.o ## these are your dependencies
CXX main.o other.o -o Prog
main.o : main.cpp
CXX CXXFLAGS -c main.cpp
other.o : other.cpp
CXX CXXFLAGS -c other.cpp
Actually, you can make it even better, but I don't remember the syntactic sugar of makefiles off the top of my head (IDE's :P)
Related
# I understand this, it runs last as Term.o and main.o have to be created
main: Term.o main.o
g++ Term.o main.o -o run
# Why use Term.h here?
Term.o: Term.cpp Term.h
g++ -c Term.cpp
# and here?
main.o: main.cpp Term.h
g++ -c main.cpp
clean:
rm *.o
I am not using Term.h when I run g++ anyway, so is there really a purpose for having them there? Though it is needed as main.cpp includes Term.h
I'm still learning how to set up a Makefile and I'm kind of lost here. I'm using windows and currently trying to fire up my Makefile for small C++ SDL project.
I have 3 .cpp files:
main.cpp
window.cpp
rect.cpp
As well as 2 extra header files:
Window.h
rect.h
So having trouble setting up everything on a Makefile
This is what i currently have:
CXXFLAGS = -Ideps/include -std=c++0x
LXXFLAGS = -Ldeps/lib -lmingw32 -lSDL2main -lSDL2
cup: main.o
g++ main.o -o cup $(LXXFLAGS)
main.o: main.cpp
g++ main.cpp -c $(CXXFLAGS)
window.o: window.cpp
g++ window.cpp -c
rect.o: rect.cpp
g++ rect.cpp -c
But I'm getting a bunch of undefined reference errors for my constructors on my command prompt.
Help please!
From the Makefile contents I read that cup binary is only created from main.o and it does not link window.o nor rect.o, which is where probably those missing references are defined. At the very least I would update the primary rule to say:
cup: main.o window.o rect.o
g++ $(LXXFLAGS) -o cup $^
Thus said, you could make even more use from implicit rules that are built into make, and, if following the standard naming for linking flags, the Makefile could be reduced even further to just a linking line (as compilation rules are implicit), e.g.:
$ cat Makefile
CXXFLAGS = -Ideps/include -std=c++0x
LDFLAGS = -Ldeps/lib
LDLIBS = -lmingw32 -lSDL2main -lSDL2
cup: main.o window.o rect.o
$(LINK.cc) $^ $(LDLIBS) -o $#
Output:
$ make
g++ -Ideps/include -std=c++0x -c -o main.o main.cpp
g++ -Ideps/include -std=c++0x -c -o window.o window.cpp
g++ -Ideps/include -std=c++0x -c -o rect.o rect.cpp
g++ -Ideps/include -std=c++0x -Ldeps/lib main.o window.o rect.o -lmingw32 -lSDL2main -lSDL2 -o cup
I recently started a small project in C++. I created a simply Makefile:
output: main.o google_api.o
g++ main.o google_api.o -o output
rm *.o
clear
./output
main.o: main.cpp
g++ -c main.cpp
test.o: google_api.cpp google_api.h
g++ -c google_api.cpp
And when I compile my code I get the next error -
non-aggregate type 'vector' cannot be initialized
with an initializer list
I am check for this issue and find that I need to add -std=c++11 support to my makefile to fix the problem. I add this command to the code:
g++ -std=c++11 main.o google_api.o -o output
But this is not make any change. I would love if someone can help me to fix this problem. Thanks
change this:
main.o: main.cpp
g++ -c main.cpp
to:
main.o: main.cpp
g++ -std=c++11 -c main.cpp
You may as well use something like this as basis for your Makefile:
CXX=g++
CXXFLAGS=-g -Wall -MMD -std=c++11
LDLIBS=-lm # list libs here
output: main.o google_api.o
clean:
$(RM) *.o *.d output
-include $(wildcard *.d)
There are also similar questions on stackoverflow: Makefile c++11 support
I've just learn something about makefile and here is my first question for it.I have main.cpp hello.cpp factorial.cpp and functions.h files
all: hello
hello: main.o factorial.o hello.o
g++ main.o factorial.o hello.o -o hello
main.o: main.cpp
g++ -c main.cpp
factorial.o: factorial.cpp
g++ -c factorial.cpp
hello.o: hello.cpp
g++ -c hello.cpp
clean:
rm -rf *o hello
In the code above, why files have an extention .o ? shouldnt be .cpp or what is the differences between using .cpp and .o
Building a C++ program is a two-stage process. First, you compile each .cpp file into a .o object file. Compiling converts the source code into machine code but doesn't resolve function calls from other source files (since they haven't been compiled yet).
main.o: main.cpp
g++ -c main.cpp
factorial.o: factorial.cpp
g++ -c factorial.cpp
hello.o: hello.cpp
g++ -c hello.cpp
Second, you link the object files together to create an executable. Linking resolves the external references in each object file.
hello: main.o factorial.o hello.o
g++ main.o factorial.o hello.o -o hello
By the way, there is a typo in the clean target. *o should be *.o.
clean:
rm -rf *.o hello
.o denote "object-files", these are files compiled from source but not yet linked into an executable or a library.
In your make-file, i.e.
main.o : main.cpp
says that main.o will be created from main.cpp using g++ -c main.cpp.
Eventually, all files with .o will create the executable hello as stated in
hello: main.o factorial.o hello.o
g++ main.o factorial.o hello.o -o hello
So, I'm making a program to test the efficiency of certain data structures. I have all the .h files and I made a very terrible makefile that probably is wrong, although it seems to work up to a point. Instead of making .o files it makes .gch files, so when it tries to acces all the .o files they are not found. This is my makefile
prog1: main.o dsexceptions.o BinarySearchTree.o SplayTree.o RedBlackTree.o AvlTree.o
g++ -Wall -g -o prog1 main.o dsexceptions.h.gch BinarySearchTree.h.gch SplayTree.h.gch RedBlackTree.h.gch AvlTree.h.gch
main.o: main.cpp AvlTree.h RedBlackTree.h SplayTree.h BinarySearchTree.h dsexceptions.h
g++ -Wall -g -c main.cpp
#shape.o: shape.cpp shape.h grid.h
# g++ -Wall -g -c shape.cpp
dsexceptions.o: dsexceptions.h
g++ -Wall -g -c dsexceptions.h
BinarySearchTree.o: BinarySearchTree.h dsexceptions.h
g++ -Wall -g -c BinarySearchTree.h
SplayTree.o: SplayTree.h dsexceptions.h
g++ -Wall -g -c SplayTree.h
RedBlackTree.o: RedBlackTree.h dsexceptions.h
g++ -Wall -g -c RedBlackTree.h
AvlTree.o: AvlTree.h dsexceptions.h
g++ -Wall -g -c AvlTree.h
clean:
rm -f main main.exe main.o dsexceptions.o BinarySearchTree.o SplayTree.o RedBlackTree.o AvlTree.o *.gch
You don't want to feed your .h files to the compiler. Only compile the .cpp file, which should include your .h files. (The .gch files are precompiled headers.) You don't need .o files for your headers, just #include them in your .cpp file.
prog1: main.o
g++ -Wall -g -o prog1 main.o
main.o: main.cpp AvlTree.h RedBlackTree.h SplayTree.h BinarySearchTree.h dsexceptions.h
g++ -Wall -g -c main.cpp
clean:
rm -f prog1 main.o
You already have the solution from bstpierre, but just for fun here's my version of your makefile:
CC = g++ -Wall -g -o $#
MODULE = AvlTree BinarySearchTree RedBlackTree SplayTree
OBJECTS = $(addsuffix .o,$(MODULES))
prog1: main.o dsexceptions.o $(OBJECTS)
$(CC) $^
main.o: $(addsuffix .h,$(MODULES))
$(OBJECTS) main.o : %.cpp %.h dsexceptions.h
$(CC) -c $<
clean:
rm -f main main.exe *.o *.gch
And just for good measure, here is my SConstruct, because SCons's so much better :)
Program('main.cpp') # Yeah, it's that simple :)
You can look at SCons here.