Chapter 26: Building Multi-File Programs with Make

Every program we have created up to this point has been compiled with a single command-line compiler directive. This is usually fine for single-file programs, even if remembering the appropriate compiler options may become a challenge. As programs are made up of multiple source code files, especially when the number of files is greater than five or six, compiling such programs becomes even more of a challenge. Building a program of several dozen or more files becomes a task fraught with potential problems. An erroneously built program will introduce a whole new set of potential bugs (the program may build but it may not actually be complete).

This was a problem faced by the creators of early versions of Unix and its family of system tools, such as yacc, lex, awk, the C compiler, the C debugger, editors, as well as Unix itself and its various subsystems. What the creators needed, and what they also created, was a build-system, called...