how to write a makefile for c program multiple files

Unless directed otherwise, make will stop when it encounters an error during the construction process. In our example the only target in the Makefile is all. It will rebuild target files if they are missing or older than the dependency files. Instead of running GCC manually, the Makefile lets you compile main.c into the hello program. It will not necessarily do all the rules in the makefile as all dependencies may not need updated. Make then reads the makefile and creates a dependency tree and takes whatever action is necessary. Multiple source files must also be separated by a space.ĭEPENDENCY LINE: TARGET FILES : SOURCE FILESĪfter the makefile has been created, a program can be (re)compiled by typing make in the correct directory. Multiple target files must be separated by a space. It is called a dependency line because the first part depends on the second part. The first part (before the colon) are target files and the second part (after the colon) are called source files.

The dependency line is made of two parts. The action line(s) must be indented with a tab.

The first line is called a dependency line and the subsequent line(s) are called actions or commands. The rules, which must begin in column 1, are in two parts. Most times, these rules are commands to compile(or recompile) a series of files. make takes as input a file (default name: Makefile) that. These rules tell the system what commands you want to be executed. make is an utility for compiling executables from many modules.

A makefile that works well in one shell may not execute properly in another shell. Without a makefile, this is an extremely time-consuming task.Īs a makefile is a list of shell commands, it must be written for the shell which will process the makefile. If you have a large program with many source and/or header files, when you change a file on which others depend, you must recompile all the dependent files. Make keeps track of the last time files (normally object files) were updated and only updates those files which are required (ones containing changes) to keep the sourcefile up-to-date. If you create more than one makefile, be certain you are in the correct directory before typing make. While in the directory containing this makefile, you will type make and the commands in the makefile will be executed. I'll break it down Barney-style in another article. A makefile is a special file, containing shell commands, that you create and name makefile (or Makefile depending upon the system). Using a Makefile is simple: make cc -o mysweetprogram main.c ls Makefile main.c mysweetprogram The Makefile that will build our MeowMeow encoder/decoder is considerably more sophisticated than this example, but the basic structure is the same. Make is Unix utility that is designed to start execution of a makefile. Makefile Tutorial - What is a Makefile? What is a Makefile?

How to write a makefile for c program multiple files