For instance, a common makefile target is clean, which generally performs actions that clean up after the compilerremoving object files and the resulting executable. The makefile tells make how to compile and link a program. These short notes describe how to easily write makefiles for compiling. Apr 03, 2016 learn to construct a basic makefile to automate building c programs. Makefile is a program building tool which runs on unix, linux, and their flavors. Simply add all source files in the makefile, set rules and execute. When make encounters an includecommand, it will stop processing the current makefile, read the included makefile and then continue where it left off. Complete makefile tutorial for beginners explained with. A makefile is a special file named as makefile only that consists of targets, dependencies and commands, structured in a way that makes it easy for a programmer to compile the program. Makefiles tutorial kyriakos stavrou tsik 6 this rule states that a. This tutorial does not even scratch the surface of what is possible using make, but is intended as a starters guide so that you can quickly and easily create your own makefiles for small to mediumsized projects.
Our examples show c programs, since they are most common, but you can use make with any programming language whose compiler can be run with a shell command. Mar 03, 2014 a makefile is a special file named as makefile only that consists of targets, dependencies and commands, structured in a way that makes it easy for a programmer to compile the program. Gcc and make a tutorial on how to compile, link and. Input for make create a file called makefile that contains a series of properly formatted commands that make will take as input. Makefile is a set of commands similar to terminal commands with variable names and targets to create object file and to remove them. Makefiles are special format files that help build and manage the. Done in unix by the makefile mechanism a makefile is a file script containing. This tutorial teaches mainly through examples in order to help quickly explain the concepts in the book. It aids in simplifying building program executables that may need various modules. Makefile is a way of automating software building procedure and other complex tasks with dependencies. Note that the final executable produced by the whole makefile is main, on line 1 in the makefile. The specification that makeuses is generally saved in a file named makefile.
How to write a simple makefile at the command prompt of your favorite shell. What is makefile for c program compilation and how to create. Here, we will use a program that deals with some geometric shapes to illustrate writing a make file to compile a program. For all the compile options we can use cl and for all the linker options we can use link. Makefile basics for linux university of colorado boulder. If either of these changes, execute the line gcc o main main. This will cause the makeprogram to read the makefile and build the first target it finds there. Among other things, cmake will generate makefiles for you.
When the source and target have the same file name except for their extensions, this rule can be. Makefile tutorial for beginner 1 technology of computing. This article is not a full tutorial, it focuses on c applications and how to use the make command and makefile to build them. Go to the previous, next section an introduction to makefiles. All the programs and examples will be available in this public folder. That is pretty much it all makefile make rules have the format of. Project structure files, dependencies instructions for files creation the make command reads a makefile, understands the project structure and makes up the executable makefile mechanism not limited to c programs. You can use the makefile with linux operation system or any other. References function reference syntax reference programming faq. In this chapter, we will discuss a simple makefile that describes how to compile and link a text editor which consists of eight c source files and three header files. This tutorial should enhance your knowledge about the structure and utility of makefile.
Makefiles use a linebased syntax in which the newline character is special. That is, the dependency lines describe the logic of. Here is the pattern rule to generate a file of prerequisites i. For the sake of simplicity, use the default installation options in your home computer. Ascertaining the steps to the coat must be split in two parts. Gnu autoconf is a tool for automatically generating configure files from a file. Makefiles the basics of c programming howstuffworks. Lets say our source code is in a file called source. When submitting code in this course, you should never name a program via the o flag unless specifically told otherwise. Hope you like this makefile tutorial for beginners.
A make file should be named either makefile first letter uppercase or makefile all lowercase. Gnu makefile documentation lecture notes foundations. The reader is accepted to have knowledge of linking, loading concepts, and how to compile and perform programs in unixlinux environment. Using make and writing makefiles swarthmore college. There is a zip file with many samples in a directory structure. The makefile can also tell make how to run miscellaneous commands when explicitly asked for example, to remove certain files as a cleanup operation. If you have any questions about make, the gnu manual should cover it. For a basic program this works well but as programs become more complex. This program will look for a file named makefile in your directory and execute it.
When make recompiles the editor, each changed c source file must be. For example, gnu make searches files in order for a file named one of gnumakefile, makefile, makefile and then runs the specified or default targets from only that file. In a single make file we can create multiple targets to compile and to remove object, binary files. This file is derived from a tutorial originally created by hector urtubia. So i create an empty file after finishing each target, with the filename equal to the targets name.
Makefile 1 compiling the source code files can be tiring, especially when you have to include several source files and type the compiling commands every time. Your contribution will go a long way in helping us. Makefile i about the tutorial makefile is a program building tool which runs on unix, linux, and their flavors. More useful still is the fact that you can create a makefile with multiple targets.
Most often, the makefile tells make how to compile and link a program in this chapter, we will discuss a simple makefile that describes how to compile and link a text editor which consists of eight c source files and three header files. Makefiles, the subject of this tutorial, provide a shortcut to compile programs, and they use c flag, which is why we are learning about it now. A complete reference for writing makefiles from simple to advanced features. Previously we learned that gnu make works in two distinct phases. The make searches the current directory for the makefile.
Our game is made up of the following source and header. Often called the default goal, this is the reason you will see all as the first target in most projects. Gnu makefile documentation lecture notes foundations of. So, if we want to create a very basic makefile for our example project. A makefile is simply a way of associating short names, called targets, with a series of commands to execute when the action is requested. However, one peculiarity of the make syntax, as opposed to say the bourne. But this isnt why make is such a nice tool for program building and management.
Gnu make also has the ability to enable a second expansion of the prerequisites only for some or all targets defined in the makefile. Makefile sets a set of rules to determine which parts of a program need to be recompile, and issues command to recompile them. First lets consider an example c program, and how to build it without make. You need a file called a makefile to tell make what to do. If you dont want it to abort when the included makefile s missing, just say include makefiles. Here is a makefile to build the traditional hello, world program. Make is a program that looks for a file called makefile or makefile, within the makefile are variables and things called dependencies. Makefile is a tool to simplify or to organize code for compilation. To use this makefile to delete the executable file and all the object files from the directory, type. To determine how the modules need to be compiled or recompiled together, make takes the help of userdefined makefiles. The file can be huge and complex, but when its done and is working, you just have to type in make and the utility uses your makefile. The make file should be in the same directory as the source code files. This is an example of the makefile for compiling the hello program. If you have prepared the makefile with name makefile, then simply write make at command prompt and it will run the makefile file.
For this to work, make has to save the state after the first run. Unix makefile tutorial for beginners learn unix makefile. The final result of the makefile should always go on line 1, which in this makefile says that the file main is dependent on main. For instance, the following example will let you type make c file to build an executable file with the given name. This tutorial is based on the topics covered in the gnu make book. But if you have given any other name to the makefile, then use the following command. We can override this behavior using a special phony target called.
The file can be huge and complex, but when its done and is working, you just have to type in make and the utility uses your makefile to do everything. The most important files in the samples are the makefiles not the c source code. A simple makefile tutorial makefiles are a simple way to organize code compilation. Makefiles are a simple way to organize code compilation. Now imagine you had a hundred source files think big, and then some more.
Which will perform the three steps shown above automatically. First makefile 1 by default, the make tool looks in the local directory for files named makefile the core component of makefiles is the rule, which takes the form. What is makefile for c program compilation and how to. This tutorial does not even scratch the surface of what is possible using make, but is intended as a starters guide so that you can quickly and easily create your own makefiles for. If either of these two files changes, the following executable lines should be executed to recreate main. So im aiming at reducing the size of my makefiles even more the previous step actually enlarged it, but it made mass adjustments easier similar to constants in large programs. A lot of this tutorial references the gnu make manual.
1193 565 1379 587 1562 1130 1248 1558 1543 114 185 707 1428 58 1347 29 715 835 160 1258 140 401 739 144 417 190 638 171 434 1288 1239 740 827 389 373 123 339 1211 870 169 358