Make/Quick-Reference
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Appendix A Quick Reference
This appendix summarizes the directives, text manipulation functions,
and special variables which GNU make
understands.
See Special Targets, Catalogue of Built-In Rules,
and Summary of Options,
for other summaries.
Here is a summary of the directives GNU make
recognizes:
define variable
define variable =
define variable :=
define variable ::=
define variable +=
define variable ?=
endef
- Define multi-line variables. See Multi-Line.
undefine variable
- Undefining variables. See Undefine Directive.
ifdef variable
ifndef variable
ifeq (a,b)
ifeq "a" "b"
ifeq 'a' 'b'
ifneq (a,b)
ifneq "a" "b"
ifneq 'a' 'b'
else
endif
- Conditionally evaluate part of the makefile. See Conditionals.
include file
-include file
sinclude file
- Include another makefile. See Including Other Makefiles.
override variable-assignment
- Define a variable, overriding any previous definition, even one from the command line. See The
override
Directive. export
- Tell
make
to export all variables to child processes by default. See Communicating Variables to a Sub-make
. export variable
export variable-assignment
unexport variable
- Tell
make
whether or not to export a particular variable to child processes. See Communicating Variables to a Sub-make
. private variable-assignment
- Do not allow this variable assignment to be inherited by prerequisites. See Suppressing Inheritance.
vpath pattern path
- Specify a search path for files matching a ‘
%
’ pattern. See Thevpath
Directive. vpath pattern
- Remove all search paths previously specified for
pattern
. vpath
- Remove all search paths previously specified in any
vpath
directive.
Here is a summary of the built-in functions (see Functions):
$(subst from,to,text)
- Replace
from
withto
intext
. See Functions for String Substitution and Analysis. $(patsubst pattern,replacement,text)
- Replace words matching
pattern
withreplacement
intext
. See Functions for String Substitution and Analysis. $(strip string)
- Remove excess whitespace characters from
string
. See Functions for String Substitution and Analysis. $(findstring find,text)
- Locate
find
intext
. See Functions for String Substitution and Analysis. $(filter pattern…,text)
- Select words in
text
that match one of thepattern
words. See Functions for String Substitution and Analysis. $(filter-out pattern…,text)
- Select words in
text
that do not match any of thepattern
words. See Functions for String Substitution and Analysis. $(sort list)
- Sort the words in
list
lexicographically, removing duplicates. See Functions for String Substitution and Analysis. $(word n,text)
- Extract the
n
th word (one-origin) oftext
. See Functions for String Substitution and Analysis. $(words text)
- Count the number of words in
text
. See Functions for String Substitution and Analysis. $(wordlist s,e,text)
- Returns the list of words in
text
froms
toe
. See Functions for String Substitution and Analysis. $(firstword names…)
- Extract the first word of
names
. See Functions for String Substitution and Analysis. $(lastword names…)
- Extract the last word of
names
. See Functions for String Substitution and Analysis. $(dir names…)
- Extract the directory part of each file name. See Functions for File Names.
$(notdir names…)
- Extract the non-directory part of each file name. See Functions for File Names.
$(suffix names…)
- Extract the suffix (the last ‘
.
’ and following characters) of each file name. See Functions for File Names. $(basename names…)
- Extract the base name (name without suffix) of each file name. See Functions for File Names.
$(addsuffix suffix,names…)
- Append
suffix
to each word innames
. See Functions for File Names. $(addprefix prefix,names…)
- Prepend
prefix
to each word innames
. See Functions for File Names. $(join list1,list2)
- Join two parallel lists of words. See Functions for File Names.
$(wildcard pattern…)
- Find file names matching a shell file name pattern (not a ‘
%
’ pattern). See The Functionwildcard
. $(realpath names…)
- For each file name in
names
, expand to an absolute name that does not contain any.
,..
, nor symlinks. See Functions for File Names. $(abspath names…)
- For each file name in
names
, expand to an absolute name that does not contain any.
or..
components, but preserves symlinks. See Functions for File Names. $(error text…)
- When this function is evaluated,
make
generates a fatal error with the messagetext
. See Functions That Control Make. $(warning text…)
- When this function is evaluated,
make
generates a warning with the messagetext
. See Functions That Control Make. $(shell command)
- Execute a shell command and return its output. See The
shell
Function. $(origin variable)
- Return a string describing how the
make
variablevariable
was defined. See Theorigin
Function. $(flavor variable)
- Return a string describing the flavor of the
make
variablevariable
. See Theflavor
Function. $(foreach var,words,text)
- Evaluate
text
withvar
bound to each word inwords
, and concatenate the results. See Theforeach
Function. $(if condition,then-part[,else-part])
- Evaluate the condition
condition
; if it’s non-empty substitute the expansion of thethen-part
otherwise substitute the expansion of theelse-part
. See Functions for Conditionals. $(or condition1[,condition2[,condition3…]])
- Evaluate each condition
conditionN
one at a time; substitute the first non-empty expansion. If all expansions are empty, substitute the empty string. See Functions for Conditionals. $(and condition1[,condition2[,condition3…]])
- Evaluate each condition
conditionN
one at a time; if any expansion results in the empty string substitute the empty string. If all expansions result in a non-empty string, substitute the expansion of the lastcondition
. See Functions for Conditionals. $(call var,param,…)
- Evaluate the variable
var
replacing any references to$(1)
,$(2)
with the first, second, etc.param
values. See Thecall
Function. $(eval text)
- Evaluate
text
then read the results as makefile commands. Expands to the empty string. See Theeval
Function. $(file op filename,text)
- Expand the arguments, then open the file
filename
using modeop
and writetext
to that file. See Thefile
Function. $(value var)
- Evaluates to the contents of the variable
var
, with no expansion performed on it. See Thevalue
Function.
Here is a summary of the automatic variables. See Automatic Variables, for full information.
$@
- The file name of the target.
$%
- The target member name, when the target is an archive member.
$<
- The name of the first prerequisite.
$?
- The names of all the prerequisites that are newer than the target, with spaces between them. For prerequisites which are archive members, only the named member is used (see Archives).
$^
$+
- The names of all the prerequisites, with spaces between them. For prerequisites which are archive members, only the named member is used (see Archives). The value of
$^
omits duplicate prerequisites, while$+
retains them and preserves their order. $*
- The stem with which an implicit rule matches (see How Patterns Match).
$(@D)
$(@F)
- The directory part and the file-within-directory part of
$@
. $(*D)
$(*F)
- The directory part and the file-within-directory part of
$*
. $(%D)
$(%F)
- The directory part and the file-within-directory part of
$%
. $(<D)
$(<F)
- The directory part and the file-within-directory part of
$<
. $(^D)
$(^F)
- The directory part and the file-within-directory part of
$^
. $(+D)
$(+F)
- The directory part and the file-within-directory part of
$+
. $(?D)
$(?F)
- The directory part and the file-within-directory part of
$?
.
These variables are used specially by GNU make
:
MAKEFILES
Makefiles to be read on every invocation of
make
. See The VariableMAKEFILES
.VPATH
Directory search path for files not found in the current directory. See
VPATH
Search Path for All Prerequisites.SHELL
The name of the system default command interpreter, usually
/bin/sh
. You can setSHELL
in the makefile to change the shell used to run recipes. See Recipe Execution. TheSHELL
variable is handled specially when importing from and exporting to the environment. See Choosing the Shell.MAKESHELL
On MS-DOS only, the name of the command interpreter that is to be used by
make
. This value takes precedence over the value ofSHELL
. See MAKESHELL variable.MAKE
The name with which
make
was invoked. Using this variable in recipes has special meaning. See How theMAKE
Variable Works.MAKE_VERSION
The built-in variable ‘
MAKE_VERSION
’ expands to the version number of the GNUmake
program.MAKE_HOST
The built-in variable ‘
MAKE_HOST
’ expands to a string representing the host that GNUmake
was built to run on.MAKELEVEL
The number of levels of recursion (sub-
make
s). See Variables/Recursion.MAKEFLAGS
The flags given to
make
. You can set this in the environment or a makefile to set flags. See Communicating Options to a Sub-make
.It is never appropriate to use
MAKEFLAGS
directly in a recipe line: its contents may not be quoted correctly for use in the shell. Always allow recursivemake
’s to obtain these values through the environment from its parent.GNUMAKEFLAGS
Other flags parsed by
make
. You can set this in the environment or a makefile to setmake
command-line flags. GNUmake
never sets this variable itself. This variable is only needed if you’d like to set GNUmake
-specific flags in a POSIX-compliant makefile. This variable will be seen by GNUmake
and ignored by othermake
implementations. It’s not needed if you only use GNUmake
; just useMAKEFLAGS
directly. See Communicating Options to a Sub-make
.MAKECMDGOALS
The targets given to
make
on the command line. Setting this variable has no effect on the operation ofmake
. See Arguments to Specify the Goals.CURDIR
Set to the absolute pathname of the current working directory (after all
-C
options are processed, if any). Setting this variable has no effect on the operation ofmake
. See Recursive Use ofmake
.SUFFIXES
The default list of suffixes before
make
reads any makefiles..LIBPATTERNS
Defines the naming of the libraries
make
searches for, and their order. See Directory Search for Link Libraries.
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