8. Functions for Transforming Text

Functions allow you to do text processing in the makefile to compute the files to operate on or the commands to use. You use a function in a function call, where you give the name of the function and some text (the arguments) for the function to operate on. The result of the function's processing is substituted into the makefile at the point of the call, just as a variable might be substituted.

8.1 Function Call Syntax		How to write a function call.
8.2 Functions for String Substitution and Analysis		General-purpose text manipulation functions.
8.3 Functions for File Names		Functions for manipulating file names.
8.4 The foreach Function		Repeat some text with controlled variation.
8.5 The if Function		Conditionally expand a value.
8.6 The call Function		Expand a user-defined function.
8.7 The value Function		Return the un-expanded value of a variable.
8.8 The eval Function		Evaluate the arguments as makefile syntax.
8.9 The origin Function		Find where a variable got its value.
8.10 The shell Function		Substitute the output of a shell command.
8.11 Functions That Control Make		Functions that control how make runs.