The order of rules is not significant, except for determining the default goal: the target for make to consider, if you do not otherwise specify one. The default goal is the target of the first rule in the first makefile. If the first rule has multiple targets, only the first target is taken as the default. There are two exceptions: a target starting with a period is not a default unless it contains one or more slashes, ‘/’, as well; and, a target that defines a pattern rule has no effect on the default goal. (See Defining and redefining pattern rules.)

Therefore, we usually write the makefile so that the first rule is the one for compiling the entire program or all the programs described by the makefile (often with a target called ‘all’). See Arguments to specify the goals.

See the following documentation for more discussion.

• Rule syntax
• Using wildcard characters in file names
• Wildcard examples
• Pitfalls of using wildcards
• The function, wildcard
• Searching directories for dependencies
• VPATH: search path for all dependencies
• The vpath directive
• Writing shell commands with directory search
• Directory search and implicit rules
• Directory search for link libraries
• Phony targets
• Rules without commands or dependencies
• Empty target files to record events
• Special built-in target names
• Multiple targets in a rule
• Multiple rules for one target
• Static pattern rules
• Syntax of static pattern rules
• Static pattern rules versus implicit rules
• Double-colon rules
• Generating dependencies automatically