Re: Makefile macros not working

[Kristof Provost]

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address@hidden wrote:
> I'm trying to use macros in this simple project:
> 
> .cpp.obj:    
>
>     g++ $? -o $@
>
> 
> Battle: Battle.obj
>
>     g++ $? -o $@
>
> 
> all: Battle
>
> But the response of make is :
> make: *** No rule to make target `Battle.obj', needed by `Battle'.  Stop.
>
> How can I use macros?
> Thanks
> Daniele
There are a couple of mistakes in your makefile:
 - To create the program you have Battle.obj as a prerequisite, but
you don't have a rule to create the prerequisite.
 - Your first rule isn't a pattern rule
 - Your first rule will also execute the link step because you forgot '-c'
 - The all: Battle rule should be the first one, as make uses the
first target as default.

Try this:

all: Battle

%.cpp,obj: %.cpp
    g++ -c $< -o $@

Battle: Battle.obj
    g++ $^ -o $@


Note the use of %, $< (rather than $?) and $^. You can find them all
in the GNU Make manual.

Kristof
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