1. Overview of make
The make utility automatically determines which pieces of a large
program need to be recompiled, and issues commands to recompile them.
This manual describes GNU make, which was implemented by Richard
Stallman and Roland McGrath. Development since Version 3.76 has been
handled by Paul Smith.
GNU make conforms to section 6.2 of IEEE Standard
1003.2-1992 (POSIX.2).
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. Indeed, make is not limited to programs. You can
use it to describe any task where some files must be updated automatically
from others whenever the others change.
Preparing and Running Make
To prepare to use make, you must write a file called
the makefile that describes the relationships among files
in your program and provides commands for updating each file.
In a program, typically, the executable file is updated from object
files, which are in turn made by compiling source files.
Once a suitable makefile exists, each time you change some source files,
this simple shell command:
suffices to perform all necessary recompilations. The make program
uses the makefile data base and the last-modification times of the files to
decide which of the files need to be updated. For each of those files, it
issues the commands recorded in the data base.
You can provide command line arguments to make to control which
files should be recompiled, or how. See section How to Run make.
