RE: ignore specific file in VPATH/vpath

[Jannick]

On Tue, 15 May 2018 19:24:06 -0400, Paul Smith wrote:
> My only suggestion other than what you've got (using pattern rules to ensure
> that the build/ versions of the files have different names than the src/
> versions) is to force the right version by providing a pathname, so that it
> won't match via vpath.  For example, you could write your rule like this:
> 
>     src_dir = ../src
>     prog: prog.o parse.o
>     vpath %.y $(src_dir)
>     vpath %.c $(CURDIR) $(src_dir)
> 
>     # remove the default rule for %.c:%.y
>     %.c: %.y
> 
>     # Define a new rule that builds a local .c
>     $(CURDIR)/%.c : %.y
>             bison ...
> 
> I'm not exactly sure that you need to add $(CURDIR) to vpath %.c but you
> probably do.
> 
> I didn't test this but it seems like it should work.

Thanks for this suggestion!

For the record here a simplified version which works and suits the objective to 
properly build in 'build'. The point is to prefix the target of c files to be 
generated with './' (was $(CURDIR) in your suggestion). That make make ignore 
src/parse.c. Moreover, the vpath statements can be replaced by one single VPATH 
statement.

VPATH = ../src
prog: prog.o parse.o

# remove the default rule for %.c:%.y
%.c: %.y

# Define a new rule that builds a local .c
./%.c : %.y
        bison -o $@ $< 

This makes script pretty simple now.

Many thanks again for taking the time.

Regards,
J.