makeHere is a summary of the features of GNU make, for comparison
with and credit to other versions of make. We consider the
features of make in 4.2 BSD systems as a baseline. If you are
concerned with writing portable makefiles, you should not use the
features of make listed here, nor the ones in Missing.
Many features come from the version of make in System V.
VPATH variable and its special meaning.
See Searching Directories for Prerequisites.
This feature exists in System V make, but is undocumented.
It is documented in 4.3 BSD make (which says it mimics System V's
VPATH feature).
MAKEFLAGS to recursive
invocations of make.
See Communicating Options to a Sub-make.
$% is set to the member name
in an archive reference. See Automatic Variables.
$@, $*, $<, $%,
and $? have corresponding forms like $(@F) and
$(@D). We have generalized this to $^ as an obvious
extension. See Automatic Variables.
-b and -m, accepted and
ignored. In System V make, these options actually do something.
make via the variable
MAKE even if -n, -q or -t is specified.
See Recursive Use of make.
.a in suffix rules. See Archive Suffix Rules. This feature is obsolete in GNU make, because the
general feature of rule chaining (see Chains of Implicit Rules) allows one pattern rule for installing members in an
archive (see Archive Update) to be sufficient.
The following features were inspired by various other versions of
make. In some cases it is unclear exactly which versions inspired
which others.
%.
This has been implemented in several versions of make.
We're not sure who invented it first, but it's been spread around a bit.
See Defining and Redefining Pattern Rules.
make
for AT&T Eighth Edition Research Unix, and later by Andrew Hume of
AT&T Bell Labs in his mk program (where he terms it
"transitive closure"). We do not really know if
we got this from either of them or thought it up ourselves at the
same time. See Chains of Implicit Rules.
$^ containing a list of all prerequisites
of the current target. We did not invent this, but we have no idea who
did. See Automatic Variables. The automatic variable
$+ is a simple extension of $^.
-W in GNU make) was (as far as we know)
invented by Andrew Hume in mk.
See Instead of Executing the Commands.
make and similar programs, though not in the
System V or BSD implementations. See Command Execution.
make by the
patsubst function before the alternate syntax was implemented
for compatibility with SunOS 4. It is not altogether clear who
inspired whom, since GNU make had patsubst before SunOS
4 was released.
+ characters preceding command lines
(see Instead of Executing the Commands) is
mandated by
IEEE Standard 1003.2-1992 (POSIX.2).
+= syntax to append to the value of a variable comes from SunOS
4 make. See Appending More Text to Variables.
archive(mem1 mem2...) to list
multiple members in a single archive file comes from SunOS 4 make.
See Archive Members.
-include directive to include makefiles with no error for a
nonexistent file comes from SunOS 4 make. (But note that SunOS 4
make does not allow multiple makefiles to be specified in one
-include directive.) The same feature appears with the name
sinclude in SGI make and perhaps others.
The remaining features are inventions new in GNU make:
-v or --version option to print version and
copyright information.
-h or --help option to summarize the options to
make.
MAKE to recursive make invocations.
See Recursive Use of make.
-C or --directory command option to change
directory. See Summary of Options.
define.
See Defining Variables Verbatim.
.PHONY.
Andrew Hume of AT&T Bell Labs implemented a similar feature with a
different syntax in his mk program. This seems to be a case of
parallel discovery. See Phony Targets.
-o or --old-file
option to pretend a file's modification-time is old.
See Avoiding Recompilation of Some Files.
This feature has been implemented numerous times in various versions
of make; it seems a natural extension derived from the features
of the C preprocessor and similar macro languages and is not a
revolutionary concept. See Conditional Parts of Makefiles.
MAKEFILES.
./ from file names, so that
./file and file are considered to be the
same file.
-lname.
See Directory Search for Link Libraries.
make, they must begin with
. and not contain any / characters.
make recursion using the
variable MAKELEVEL. See Recursive Use of make.
MAKECMDGOALS. See Arguments to Specify the Goals.
vpath search.
See Searching Directories for Prerequisites.
make has a very, very limited form of this
functionality in that it will check out SCCS files for makefiles.
MAKE_VERSION gives the version number of
make.