Chapter 6: How to Use Variables 75
.RECIPEPREFIX
The first character of the value of this variable is used as the character make
assumes is introducing a recipe line. If the variable is empty (as it is by de-
fault) that character is the standard tab character. For example, this is a valid
makefile:
.RECIPEPREFIX = >
all:
> @echo Hello, world
The value of .RECIPEPREFIX can be changed multiple times; once set it stays
in effect for all rules parsed until it is modified.
.VARIABLES
Expands to a list of the names of all global variables defined so far. This
includes variables which have empty values, as well as built-in variables (see
Section 10.3 [Variables Used by Implicit Rules], page 115), but does not include
any variables which are only defined in a target-specific context. Note that any
value you assign to this variable will be ignored; it will always return its special
value.
.FEATURES
Expands to a list of special features supported by this version of make. Possible
values include, but are not limited to:
‘archives’
Supports ar (archive) files using special file name syntax. See
Chapter 11 [Using make to Update Archive Files], page 129.
‘check-symlink’
Supports the -L (--check-symlink-times) flag. See Section 9.7
[Summary of Options], page 104.
‘else-if’ Supports “else if” non-nested conditionals. See Section 7.2 [Syntax
of Conditionals], page 78.
‘jobserver’
Supports “job server” enhanced parallel builds. See Section 5.4
[Parallel Execution], page 47.
‘oneshell’
Supports the .ONESHELL special target. See Section 5.3.1 [Using
One Shell], page 44.
‘order-only’
Supports order-only prerequisites. See Section 4.2 [Types of Pre-
requisites], page 22.
‘second-expansion’
Supports secondary expansion of prerequisite lists.
‘shortest-stem’
Uses the “shortest stem” method of choosing which pattern, of
multiple applicable options, will be used. See Section 10.5.4 [How
Patterns Match], page 122.
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