Re: Question on targets and goals

[Jeffrey Walton]

On Mon, Aug 8, 2011 at 8:13 AM, Paul Smith <address@hidden> wrote:
> On Mon, 2011-08-08 at 06:51 -0400, Jeffrey Walton wrote:
>> I would like to invoke make with a debug or release configuration, but
>> without a rule:
>>     `make debug` or `make release`
>>
>> Later:
>>
>> ifeq ($(MAKECMDGOALS),debug)
>>   CXXFLAGS += -DDEBUG=1 -g3 -ggdb -O0
>> endif
>>
>> Because I don't have a rule, I'm getting a make error:
>>     make: *** No rule to make target `debug'.  Stop.
>
> Why can't you add a rule?  Just say:
>
>        debug release: all
>
> In fact if you do this, you can take advantage of target-specific
> variable inheritance, like this:
>
>        debug release: all
>        debug: CXXFLAGS += -DDEBUG=1 -g3 -ggdb -O0
I did not know I could do this (I don't believe Stallman covers it in
his book on GNU Make, or perhaps he did not give an example).

I did try the following, which made things ill:
    debug:
        CXXFLAGS += -DDEBUG=1 -g3 -ggdb -O0

>
>
> If you can't add a rule and you can't use variable assignments
> (regarding Greg's suggestion), then I think you're out of luck.  It
> seems you want a new behavior without changing any code, which is seldom
> possible in the world of computers :-)
I think things might be workable now.

Thanks for the suggestions,
Jeffrey Walton