Re: goal argument to make in any automatic variable ? what is @[ $(origin $(*)) != 'undefined' ] && .. for ?

[Paul Smith]

On Tue, 2013-08-13 at 17:02 +0200, andreas graeper wrote:
> target: xxx
>   @[ "$(origin $(*))" != "undefined" ] && echo "$($(*))"
> 
> `make -f that-makefile goal` is called from shell script
> 
> i tried to call a test makefile with and without goal
> 
>  make
> and
>  make <goal>
> and i thought i could find the goal in $0 or $1 .. . is there a
> automatic variable that tells me whether an explicit goal was given as
> argument.

No; automatic variables are values that are only relevant for a given
target.  "Whether there was an explicit goal given as a command line
argument" is a global setting for the entire make invocation, so doesn't
belong there.

Look up the MAKECMDGOALS variable in the GNU make manual.

> and what is $*. in which cases it can be != 'undefined' ( result from
> $(origin $(*)) )

The meaning of $* can be found in the GNU make manual section on
automatic variables.  It means the part of the target which matches a
pattern.  Note it will be empty if there's no pattern or suffix that
matches this target.

However note that origin takes the NAME of a variable.  So by passing it
$* the code is checking to see if the variable with the NAME $* is
defined or not.  If it wanted to see if the variable "*" itself is
defined or not, it would call $(origin *)

So in your example, if $* is "target", then this checks to see if the
variable $(target) is defined or not.