#Make and Makefiles
Make is a tool that can be used to compile code, as well as completing
other tasks. Type man make on the command line to get the full description
and documentation.
To use it, you write a configuration file for your project named makefile or
Makefile, with instructions that make will follow.
##Compiling C Programs with Make
In the Advanced Compilation notes, we saw how you can choose to only re-compile object files that are out of date when updating your C program. However, keeping track of which files to recompile manually would be more trouble than it's worth.
make can automatically recompile of only the outdated files.
To set this up, we need to tell make about any targets, (files to
compile), and any dependencies, (files that the targets depend on).
For our example Fizz Buzz project, here is an makefile:
# below, 'fizz.o' is the target, and 'fizz.c' 'fizz.h' are the dependencies
fizz.o: fizz.c fizz.h
gcc -c fizz.c # this line gets run if the dependencies are out of date
# below, 'buzz.o' is the target, and 'buzz.c' 'buzz.h' are the dependencies
buzz.o: buzz.c buzz.h
gcc -c buzz.c # this line gets run if the dependencies are out of date
# below, 'fizz_buzz' is the target and 'fizz_buzz.c' 'fizz.o' 'buzz.o' are dependencies
fizz_buzz: fizz_buzz.c fizz.o buzz.o
gcc fizz_buzz.c fizz.o buzz.o -o fizz_buzz##Gotchas
Windows users beware: make may have a different name on Windows.
"MinGW" includes a version of make called mingw32-make and Microsoft has
their own version called NMAKE. Also, some makefiles may not work on
different operating systems.
Use tabs, not spaces: When writing a makefile, you must use tabs and
not spaces. If you use spaces, it just won't work.
References:
Head First C, p. 198-205