Re: Expandable dependencies variables

[Miguel Guedes]

On 09/11/12 23:24, Paul Smith wrote:
> Or, finally, you can go old-school and use auto-generated included
> makefiles, which will work with virtually every version of GNU make out
> there:
>
>          BINARIES := foo bar
>
>          foo_OBJECTS := foo_obj_1 foo_obj_2
>          bar_OBJECTS := bar_obj_1 bar_obj_2
>
>          -include generated.mk
>          generated.mk: Makefile
>            @($(foreach B,$(BINARIES),echo $B: $($B_OBJECTS);):) > $@
>

Thank you for your input, Paul!

After weighing the pros and cons I've come to the conclusion that it's 
best to use GNU Autoconf/Automake after all.

There's one thing I would simply love to accomplish with Automake 
though: the ability to extend rules without overriding them. For 
instance, how would one print a custom message in a specific format 
(i.e. color) each time a source file is compiled and then linked?

For instance, in a traditional Makefile I would simply add the following 
rule:

%.o: %.c
        @echo -e "[C] `basename $<`
        @$(CC) $(CFLAGS) -c $< -o $@

$(bin): $(bin_OBJECTS)
        @echo "\033[1;32m[L] `basename address@hidden"
        @LINK_LOG="/tmp/`basename address@hidden"; \
                [ -f $$LINK_LOG ] && rm $$LINK_LOG; \
                $(CXX) $(CXX_FLAGS) -o $@ $(EXE_OBJECTS) \
                        $(LIBRARIES) 2>$$LINK_LOG ; \
                EXIT_CODE=$$?; \
                if [ ! $$? -eq 0 ]; then \
                        cat "$$LINK_LOG"; \
                        exit $$EXIT_CODE; \
                fi;

The above would result in something like:

[C] foo.c
[C] bar.c
[L] bin         # in yellow

But how do you setup a Makefile.am such that compilation and linking 
rules are extended in Makefile.in and the generated Makefile.am still 
contains the normally generated compile/link rules logic - so 
dependencies, compilation and linking logic is kept and *not* overriden. 
I've had a look at the Automake hooks but they seem to be executed after 
the main rule.