GNU `make'

Node:Values, Next:Setting, Previous:Advanced, Up:Using Variables

### How Variables Get Their Values

Variables can get values in several different ways:

- You can specify an overriding value when you run `make`. See Overriding Variables.
- You can specify a value in the makefile, either with an assignment (see Setting Variables) or with a verbatim definition (see Defining Variables Verbatim).
- Variables in the environment become `make` variables. See Variables from the Environment.
- Several automatic variables are given new values for each rule. Each of these has a single conventional use. See Automatic Variables.
- Several variables have constant initial values. See Variables Used by Implicit Rules.