I suggest that you always wrap it in the wildcard function, because otherwise you may fall into a common pitfall described below. * searches your filesystem for matching filenames. all: f1.o f2.oĮcho # Equivalent to: # f1.o # echo # f2.o # echo Automatic Variables and Wildcards * Wildcardīoth * and % are called wildcards in Make, but they mean entirely different things. When there are multiple targets for a rule, the commands will be run for each is an automatic variable that contains the target name. Making multiple targets and you want all of them to run? Make an all target.
When you run make blah in the terminal, it will build a program called blah in a series of steps: The following Makefile has three separate rules. These files need to exist before the commands for the target are run.
Some code editors like Microsoft Visual Studio have their own built in build tools. Popular C/C++ alternative build systems are SCons, CMake, Bazel, and Ninja. If any file's dependencies changes, then the file will get recompiled: Here's an example dependency graph that you might build with Make. This tutorial will focus on the C/C++ compilation use case. It can be used beyond programs too, when you need a series of instructions to run depending on what files have changed. Other languages typically have their own tools that serve a similar purpose as Make. In the vast majority of cases, C or C++ files are compiled. Makefiles are used to help decide which parts of a large program need to be recompiled. Good luck, and I hope you are able to slay the confusing world of Makefiles! Getting Started Why do Makefiles exist? If you mostly understand Make, consider checking out the Makefile Cookbook, which has a template for medium sized projects with ample comments about what each part of the Makefile is doing. Each topic has a brief description and a self contained example that you can run yourself. I've condensed the most critical knowledge into this guide. To solve this, I sat down for several weekends and read everything I could about Makefiles. They seemed awash with hidden rules and esoteric symbols, and asking simple questions didn’t yield simple answers. I built this guide because I could never quite wrap my head around Makefiles.