Re: a syntax for multitarget rules

[Tim Murphy]

To save typing here's an example of some of the possible hacks:
http://www.cmcrossroads.com/article/rules-multiple-outputs-gnu-make

You'll see the problem with "chaining" dependencies - there is a situation
when a file is deleted and running make again doesn't recreate it.
Basically only one target in your chain has a "command" or "recipe" so if
that file exists then make won't run the recipe even if some other file in
the chain is missing.

Disclaimer: I work with Eric and although some of his articles are aimed at
promoting emake and could wind a gmake aficionado up the wrong way, there
is something to be said for #pragma or some other "fairly generic" way to
implement new features so that implementing them becomes a non-issue.

e.g. if I wanted to implement CRC uptodate checks for specific targets
(small high value ones like header files that can cause a cascade of builds
if they change) but not for big ones (600MB ISOs) then how would one
indicate such handling for that target?  ".WHATEVER: mytarget" is one way -
I'm not the worlds greatest fan of it as it's really only suited to binary
on-off settings but in this case why not use that?  It would be best to
have a way that allows one to not have to debate too much in future.

As for implementation - I guess I couldn't offer because of my position
which is frustrating :-).

Regards,

Tim

On 13 November 2014 21:46, Steven Simpson <address@hidden> wrote:

> Hi,
>
> On 11/11/14 05:44, Nicholas Clark wrote:
>
>> foo1.out report.txt foo2.out foo3.out non_pattern.bit: TASK1_OUTPUTS
>> fob1.out static_file.bmm fob2.out fob3.out project_file.ngc: TASK2_OUTPUTS
>>
>> TASK1_OUTPUTS: source1_a.src source1_b.src
>>      $(EXTERNAL_UTIL_1) source1_a.src source1_b.src
>>
>> TASK2_OUTPUTS: source2_a.src source2_b.src
>>      $(EXTERNAL_UTIL_2) source2_a.src source2_b.src
>>
>> .GROUPTARGET: TASK1_OUTPUTS TASK2_OUTPUTS
>>
>
>
> Is it not sufficient to create an empty target?:
>
> task1.done: source1_a.src source1_b.src
>     $(EXTERNAL_UTIL_1) source1_a.src source1_b.src
>     touch $@
>
> task2.done: source2_a.src source2_b.src
>     $(EXTERNAL_UTIL_2) source2_a.src source2_b.src
>     touch $@
>
> If you need any of the files created by task 2, you just name task2.done
> as the prerequisite.  Or have I misunderstood?...
>
>  In the example above, any dependencies of .GROUPTARGET would be a
>> target-group. Each target group could be treated sort of like a
>> conditional
>> PHONY that would run if any of the group's members were out-of-date.
>>
>
> Are you saying that $(EXTERNAL_UTIL_1) won't necessarily update all of
> TASK1_OUTPUTS (otherwise, they would all be out-of-date together)?
>
> Cheers,
>
> Steven
>
>
> _______________________________________________
> Help-make mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/help-make
>



-- 
You could help some brave and decent people to have access to uncensored
news by making a donation at:

http://www.thezimbabwean.co.uk/friends/