GNU Autoconf, Automake, and Libtool

3.1. Targets and Dependencies

The make program attempts to bring a target up-to-date by bringing all the target's dependencies up-to-date. These dependencies may have further dependencies. Thus, a potentially complex dependency graph forms when processing a typical 'Makefile':

all: foo

foo: foo.o bar.o baz.o

.c.o:
        $(CC) $(CFLAGS) -c $< -o $@@

.l.c:
        $(LEX) $< && mv lex.yy.c $@@

From a simple file that looks like this one, we can draw a dependency graph such as the one in Figure 3.1.

Figure 3.1. Example Dependency Graph.

Unless the 'Makefile' contains a directive to make, all targets are assumed to be filenames, and rules must be written to ...