Re: Parallel make not working the way I expect...

[Paul Smith]

On Fri, 2007-02-09 at 23:54 +0000, David Wuertele wrote:

> > Choice 2) use a pattern rule with multiple targets so that make knows
> > that one command builds all of them.  You should arrange for the files
> > to have names that follow some sort of pattern (all have the same
> > prefix, of suffix, or *something* in common) so that the patterns you
> > give use to match them make some sense.

> Except:  maybe I could use the subdirectory as a prefix?  I tried this:
> 
> LOTS_OF_FILES := dir/one dir/two dir/three dir/four dir/five dir/six
> 
> all: $(LOTS_OF_FILES)
> 
> COMMAND_WHICH_BUILDS_LOTS_OF_FILES := for file in $(LOTS_OF_FILES); do mkdir 
> -p
> `dirname $$file` && echo hello >> $$file; done
> 
> $(LOTS_OF_FILES): dir/%: Makefile
>       $(COMMAND_WHICH_BUILDS_LOTS_OF_FILES)

> Is that what you mean by a pattern rule?

No.  That is a static pattern rule; a static pattern rule (confusingly
enough) is really just a shorthand for writing lots of explicit rules.

You have to use the syntax:

        %/one %/two %/three %/four %/five %/six : Makefile
                $(COMMAND_WHICH_BUILDS_LOTS_OF_FILES)

to get a pattern rule.

If you don't want to/can't do that, then you have to use a "sentinel
file" model.  Something like this:

        all: $(LOTS_OF_FILES)

        $(LOTS_OF_FILES): .sentinel

        .sentinel: Makefile
                $(COMMAND_WHICH_BUILDS_LOTS_OF_FILES)
                touch $@

-- 
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 Paul D. Smith <address@hidden>          Find some GNU make tips at:
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