Makefile that compiles all cpp files in a directory into separate executable

9
votes

I am now studying C++. I want a makefile which will compile all of the cpp files in the current directory to separate executables. For example:

In a directory there are 3 c++ files, such as examp1.cpp, examp2.cpp and examp3.cpp. I want a makefile which will compile and link them and give examp1.exe, examp2.exe and examp3.exe

I have created a bash script to compile all of them and create exes but I think; that's not the exact way to do this.

I have a a Makefile for ".c", but that does not seem to work here. It is only creating object files and not actually linking it. It is as follows:

SRCS=$(wildcard *.c)
OBJS=(SRCS:.c=.o)
all: $(OBJS)

The above code compiles all the new and modified ".c" files to ".o" files with same name in the current directory.

The bash script I am using to create executables is as follows:

for i in ./*.cpp
do
   g++ -Wno-deprecated $i -o `basename $i .cpp`".exe"
done

This means I want whatever ".cpp" files I put in that directory, by using a simple "make all" or anything like that it should compile.

4
c++makefile
Have you made any attempt at trying to create the makefile? If so post it so we can help you. There is documentation available to get started. – Joe
The versions of make vary from one supplier to another. What make are you using? Are you using GNU Make on Linux? Microsoft Make on Windows/Visual C++? – Robᵩ
Have you tried writing a makefile that will compile one source file and produce an executable? – Beta

4 Answers

18
votes

A minimal Makefile that does what you want would be:

#Tell make to make one .out file for each .cpp file found in the current directory
all: $(patsubst %.cpp, %.out, $(wildcard *.cpp))

#Rule how to create arbitary .out files. 
#First state what is needed for them e.g. additional headers, .cpp files in an include folder...
#Then the command to create the .out file, probably you want to add further options to the g++ call.
%.out: %.cpp Makefile
    g++ $< -o $@ -std=c++0x

You'll have to replace g++ by the compiler you're using and possibly adjust some platform specific setting, but the Makefile itself should work.

3
votes

This is the Makefile that I use

CC = gcc
CFLAGS = -g -O2 -std=gnu99 -static -Wall -Wextra -Isrc -rdynamic -fomit-frame-pointer
all: $(patsubst %.c, %.out, $(wildcard *.c))
%.out: %.c Makefile
    $(CC) $(CFLAGS) $< -o $@ -lm
clean:
    rm *.out

You should paste it somewhere in your home and whenever you change the dirctory just copy it there. I use an alias in my ~/.basrc to copy it

alias get_makefile_here='cp ~/Makefile ./'

Simply press make and bam, you're done. Also notice the fact that once you're done with the old files it will not rebuild their executable.

1
votes

My answer builds on top of the answer by @Haatschii

I don't prefer to have the .out prefix to my binaries. Also I used his existing Make syntax to perform clean as well.

CXX=clang++
CXXFLAGS=-Wall -Werror -std=c++11

all: $(patsubst %.cpp, %.out, $(wildcard *.cpp))

%.out: %.cpp Makefile
        $(CXX) $(CXXFLAGS) $< -o $(@:.out=)

clean: $(patsubst %.cpp, %.clean, $(wildcard *.cpp))

%.clean:
        rm -f $(@:.clean=)
0
votes

The simplest makefile you can create that might work for you is this:

all: examp1.exe examp2.exe examp3.exe

That will use make's default rules to create your three programs.