Re: [Qemu-devel] [PATCH 09/11] qapi: add qapi-errors.py

[Eric Blake]

On 07/26/2012 06:38 AM, Eric Blake wrote:
>>> Paolo, Eric, maybe you can provide advice on how to best tell make that
>>> a recipe generates multiple files.
>>
>> Hmm, I would just do
>>
>> qapi-errors.h: qapi-errors.c
>> qapi-errors.c: $(SRC_PATH)/qapi-schema-errors.json 
>> $(SRC_PATH)/scripts/qapi-errors.py
>>      $(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-errors.py -o 
>> "." < $<, "  GEN   $@")
>>
>> I think that's what I usually saw for bison (which creates both .h and .c).
> 
> Indeed, per
> https://www.gnu.org/software/automake/manual/automake.html#Multiple-Outputs,
> that is an appropriate solution for a 2-file generation.

Or, since we depend on GNU make, we can use pattern rules instead
(untested):

%-errors.h %-errors.c: \
   %(SRC_PATH)/%-schema-errors.json $(SRC_PATH)/srcipts/%-errors.py
        $(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-errors.py -o
"." < $<, "  GEN   $@")

https://www.gnu.org/software/automake/manual/make.html#Pattern-Examples

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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