Question

I have to frequently compile small program and run it. Since, it was tedious to write compile command g++ -W -Wall file.cpp -o out everytime for each cpp file, I wrote one small scripts, which does the compiling.

Here is the script that I wrote

#!/bin/bash
g++ -W -Wall $1 -o $1.out

So, if I have to compile file.cpp, I will do compile file.cpp and it will create file.cpp.out executable for me.
And, such file.cpp dont have any header files or any other dependencies.

I know how to write makefile for particular file.cpp like this (very simple case)

file: file.cpp
    g++ -W -Wall file.cpp -o file

but if I have to compile file2.cpp, I have to change above makefile again or write new. So, what I want to do is, when I give make file.cpp command it will produce file as executable. And when I give make file2.cpp it will produce file2 as executable, and similarly for other cpp files.

Answer 1

export CXXFLAGS="-W -Wall"
rm Makefile
make file1

Make has sane defaults. You don’t have to write a makefile to use make.

Make has a set of generic rules, which get apply automatically when there is no specific rule. One of them is to make ‘file’ out of ‘file.cpp’ using a C++ compiler with flags from environment variable CXXFLAGS. This works a bit like you want…