Re: Multiple pattern-specific variable assignments

[Adrian Ashley]

Paul,

>   aa> Can anyone suggest a way to accomplish multiple
>   aa> pattern-specific variable assignments?  This
>   aa> fragment illustrates what I'm trying to do.
>
>   aa> foo-%.o : CFLAGS += -DVARIANT=FOO
>   aa> bar-%.o : CFLAGS += -DVARIANT=BAR
>
>   aa> %-gcc.o : CFLAGS += -DGCC
>   aa> %-other.o : CFLAGS += -DOTHERCC
>
> You could put one of these into a different variable, like:
>
>   %-gcc.o : CCTYPE = -DGCC
>   %-other.o : CCTYPE = -DOTHERCC
>
> Then:
>
>  %-gcc.o: %.c
>          $(CC_GCC) $(CCTYPE) $(CFLAGS) -o $@ -c $<
>
>  %-other.o: %.c
>          $(CC_OTHER) $(CCTYPE) $(CFLAGS) -o $@ -c $<

Tried that:

    $ cat Makefile
    CC_GCC=gcc
    CC_OTHER=another-cc
    CFLAGS = -DBASIC
    foo-%.o : CFLAGS += -DVARIANT=FOO
    bar-%.o : CFLAGS += -DVARIANT=BAR
    %-gcc.o : CCTYPE = -DGCC
    %-other.o : CCTYPE = -DOTHERCC
    %-gcc.o: %.c
        $(CC_GCC) $(CCTYPE) $(CFLAGS) -o $@ -c $<
    %-other.o: %.c
        $(CC_OTHER) $(CCTYPE) $(CFLAGS) -o $@ -c $<

    $ make foo-gcc.o
    gcc  -DBASIC -DVARIANT=FOO -o foo-gcc.o -c foo.c

It's still stopping as soon as it's matched "foo-%.o".  If I reorder the
patterns:

    $ cat Makefile
    [...]
    %-gcc.o : CCTYPE = -DGCC
    %-other.o : CCTYPE = -DOTHERCC
    foo-%.o : CFLAGS += -DVARIANT=FOO
    bar-%.o : CFLAGS += -DVARIANT=BAR
    [...]

then it matches "%-gcc.o" instead:

    $ make foo-gcc.o
    gcc -DGCC -DBASIC -o foo-gcc.o -c foo.c

I hesitate to call this a bug, as the documentation does say that pattern
rule matching proceeds until the first match and then stops.  But perhaps
there's a case for arguing that if the effect is only to set target- or
pattern-specific variables, then all patterns which match should do so
cumulatively (perhaps excepting terminal ones?)

Or is there a Cunning Trick?

Thanks,
--
Adrian Ashley
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