Makefiles

make is a powerful utility which allows programs to be broken down into small pieces, and based on the date of modification, the pieces not up-to-date are recompiled and/or linked. A basic makefile is shown below.

<program> : <objectfiles> <libraries>
  cc -o <program> <objectfiles> <libraries> -lm
.c.o :
  cc -c $*.c

In this example, the program being compiled is called mytrans. The object file needed is mytrans.o and the two libraries are hminlib.a and hmlib.a. The object files are created by compiling the source code files, mytrans.c, which are not explicitly listed in the makefile. After the substitutions are made, the makefile needed to create the program mytrans looks like this:

mytrans : mytrans.o hminlib.a hmlib.a
  cc -o mytrans mytrans.o hminlib.a hmlib.a -lm
.c.o :
  cc -c $*.c