Re: how to explain this line ?

[Paul Smith]

On Tue, 2013-02-05 at 13:45 +0800, horseriver wrote:
>   $(filter-out FORCE,$^) represent what?

$^ is an automatic variable, which are described here:

http://www.gnu.org/software/make/manual/html_node/Automatic-Variables.html

$^ will expand to the list of prerequisites of the rule which are newer
than the target.

The filter-out function is described here:

http://www.gnu.org/software/make/manual/html_node/Text-Functions.html

It returns all the words in the list which do not match first argument.

So in this case, that operation returns all the prerequisites of the
rule which are newer than the target, and which are not the "FORCE"
prerequisite.


BTW: note that the online documentation always documents the latest
version of GNU make.  The version you're using may be older and may not
support all features described in the manual.  You should read the local
version of the manual that comes with your local version of GNU make to
get accurate information.