ch Page 3 Friday, March 25, PM Chapter 1 CHAPTER 1 How to Write a Simple Makefile The mechanics of programming usually follow a fairly simple routine of editing source files, compiling the source into an executable form, and debugging the result This is clearly pointed out by the writer of Makefile, the files to be generated, the dependent files of the files, and the generated commands. 2. Obscure rules: Since our make has the function of automatic deduction, obscure rules allow us to write MakeFile relatively simply and Sep 27, · Creating a simple GCC Makefile in Linux using C Language. Makefile contains recipes implemented on various files to achieve a target. A target is the output file which is created by linking and compiling the base files. We are going to use GCC compiler to Makefile contains recipes implemented on various files to achieve a target
Makefile learning one - Fire Heart
I built this guide because I could never quite wrap my head around Makefiles. To solve this, I sat down for several weekends and read everything I could about Makefiles. I've condensed the most critical knowledge into this guide. Each topic has a brief description and a self contained example that you can run yourself.
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. Makefiles are used to help decide which parts of a large program need to be recompiled. Other languages typically have their own tools that serve a similar purpose as Make. It can be used beyond programs too, when you need a series of instructions to run depending on what files have changed.
Here's an example dependency graph that you might build with Make. If any file's dependencies changes, then the file will get recompiled:.
Some code editors like Microsoft Visual Studio have their own built in build tools. For Java, there's AntMavenand Gradle. Other languages like Go and Rust have their own build tools. Interpreted languages like Python, Ruby, and Javascript don't require an analogue to Makefiles. The goal of Makefiles is to compile whatever files need to be compiled, based on what files have changed. But when files in interpreted languages change, nothing needs to get recompiled, how to write a simple makefile.
When the program runs, the most recent version of the file is used. To run these examples, you'll how to write a simple makefile a terminal and "make" installed. For each example, put the contents in a file called Makefileand in that directory run the command make. Let's start with the simplest of Makefiles:. That's it! If you're a bit confused, here's a video that goes through these steps, along with describing the basic structure of Makefiles.
The following Makefile has three separate rules. When you run make blah in the terminal, it will build a program called blah in a series of steps:.
It will first look at its list of dependenciesand if any of them are older, it will first run the targets for those dependencies, and then run itself. The second time this is run, neither target will run because both targets exist. clean is often used as a target that removes the output of other targets, but it is not a special word in make. I suggest that you always wrap it in the wildcard function, because otherwise you may fall into a common pitfall described below. It's oddly unhelpful and I find it more confusing than useful.
There are many automatic variablesbut often only a few show up:. Make loves c how to write a simple makefile. And every time it expresses its love, things get confusing. Here's the syntax for a new type of rule called a static pattern:.
Whatever was matched is called the stem. The stem is then substituted into the prereq-pattern, to generate the target's prereqs. A typical use case is to compile. c files into. o files. Here's the manual way :. While I introduce functions later on, I'll foreshadow what you can do with them.
The filter function can be how to write a simple makefile in Static pattern rules to match the correct files. In this example, I made up the. raw and. result extensions, how to write a simple makefile. Perhaps the most confusing part of make is the magic rules and variables that are made. How to write a simple makefile a list of implicit rules:.
Double-Colon Rules are rarely used, but allow multiple rules to be defined for the same target. If these were single colons, a warning would be printed and only the second set of commands would run.
Add an before a command to stop it from being printed You can also run make with -s to add an before each line. Add -k when running make to continue running even in the face of errors.
Helpful if you want to see all the errors of Make at once. Add a - before a command to suppress the error Add -i to make to have this happen for every command. The export directive takes a variable and makes it accessible to sub-make commands. In this example, cooly is exported such that the makefile in subdir can use it. Note: export has the same syntax as sh, but they aren't related although similar in function. There's a nice list of options that can be run from make. Check out --dry-run--touch--old-file.
You can have multiple targets to make, i. make clean run test runs the clean how to write a simple makefile, then runand then test.
Recursive definitions will give an infinite loop error. Spaces at the end of a line are not stripped, but those at the start are. String Substitution is also a really common and useful way to modify variables. Also check out Text Functions and Filename Functions. You can override variables that come from the command line by using override. It has nothing to do with being a function. Note here that it's a bit different than having a semi-colon between commands, because each is run in a separate shell, as expected.
This example shows you how to test make flags with findstring and MAKEFLAGS. Run this example with make -i to see it print out the echo statement, how to write a simple makefile.
Functions are mainly just for text processing. You can make your own using the call builtin function. Make has a decent amount of builtin functions, how to write a simple makefile. Note: don't add extra spaces for this shorthand. It will be seen as a search or replacement term. It converts one list of words separated by spaces to another. var is set to each word in list, and text is expanded for each word.
This appends an exclamation after each word:. if checks if the first argument is nonempty. If so runs the second argument, otherwise runs the third. Make supports creating basic functions. You then call the function with the special call function. are the params. The include directive tells make to read one or more other makefiles. It's a line in the makefile makefile that looks like this:.
This is particularly useful when you use compiler flags like -M that create Makefiles based on the source. For example, if some c files includes a header, that header will be added to a Makefile that's written by gcc. I talk about this more in the Makefile Cookbook. Use vpath to specify where some set of prerequisites exist. You can also do this globallyish with the variable VPATH.
PHONY to a target will prevent make from confusing the phony target with a file name. In this example, if the file clean is created, make clean will still be run.
PHONY is great to use, but I'll skip it in the rest of the examples for simplicity. The make tool will stop running a rule and will propogate back to prerequisites if a command returns a nonzero exit status. This will happen for all targets, not just the one it is before like PHONY. It's a good idea to always use this, how to write a simple makefile, even though make does not for historical reasons, how to write a simple makefile.
The neat thing about this makefile is it automatically determines dependencies for you. Learn Makefiles. Start the Tutorial Makefile Cookbook. Makefile Tutorial. Getting Started Why do Makefiles exist?
A Simple Makefile Tutorial
, time: 7:04Using "make" and writing Makefiles
ch Page 3 Friday, March 25, PM Chapter 1 CHAPTER 1 How to Write a Simple Makefile The mechanics of programming usually follow a fairly simple routine of editing source files, compiling the source into an executable form, and debugging the result This is simple makefile tutorial. And I am sure you get your basics done with this tutorial. Now you can implement makefile in your project whether if it is a small or a big project. Now action on you Write makefile for your project. Include all the source files in the makefile. Set the rule and dependencies according to your project needs The simplest makefile you could create would look something like: Makefile 1 hellomake: hellomake.c hellofunc.c gcc -o hellomake hellomake.c hellofunc.c -I. If you put this rule into a file called Makefile or makefile and then type make on the command
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