Re: Make rule not taken although it matches

[Sebastian Schuberth]

Here's the solution to the problem: make has a built-in implicit rule to 
make .o files from .c files. I was pretty sure my rule to create .o 
files from .s files would override this implicit rule, but it does so 
ONLY IF THE .s FILE ALREADY EXISTS! So the implicit rule has to be 
explicitly canceled <grin> by adding

%.o: %.c

(with no commands) to the top of the file. For more information read:

http://www.gnu.org/software/make/manual/html_chapter/make_10.html#SEC105
http://www.gnu.org/software/make/manual/html_chapter/make_10.html#SEC114

--
Sebastian Schuberth

> Hi,
>
> in my makefile I have two simple rules:
>
> prefix_%.s: prefix_%.c
>     # Do something
>
> prefix_%.o: prefix_%.s
>         # Do something
>
> The file prefix_test.c exists. When I type "make prefix_test.o", instead 
> of my rule some default rule (which is not present in the file) 
> launching "cc" is run. However, running "make prefix_test.s" works, and 
> running "make prefix_test.o" afterwards (so prefix_test.s exists) works 
> then, too. Why is that? Why can't I create both "prefix_test.s" and 
> "prefix_test.o" in a single step by launching "make prefix_test.o"?
>
> Thanks for any insights.