Re: RFC: .ALIAS builtin pseudotarget

[Glenn Fowler]

I've attached three makefiles to illustrate the difference between
        using a variable,       Makefile.var
        a .PHONY target,        Makefile.phony
        and an .ALIAS target    Makefile.alias
to hold a common prereq list for a collection of targets.
Makefile.alias assumes the .ALIAS patch has been applied.

Also attached is a shell script test.alias to show the
makefiles in action. This script produces the following
on my linux box:

var.1   checks=1017755  commands=2000   files=2000
var.2   checks=2005756  commands=0      files=2000
phony.1 checks=19759    commands=2000   files=2000
phony.2 checks=13759    commands=1000   files=2000
alias.1 checks=20761    commands=2000   files=2000
alias.2 checks=9762     commands=0      files=2000

The varable solution forces make to do a million checks, but
the second run results in no actions executed. The phony
solution does better on the checks but the second run
re-executes half the actions. The alias solution cuts down
on the checks and executes no actions on the second run.

-- Glenn Fowler -- AT&T Research, Florham Park NJ --

Makefile.var
Description: Text document

Makefile.phony
Description: Text document

Makefile.alias
Description: Text document

test.alias
Description: application/sh