Re: GNU Makefile ule

[Paul Smith]

On Thu, 2022-06-23 at 09:26 +0000, Ming Cheng wrote:
> modules := abc
> abc_type := static_library
> abc_target := libabc.a

These lines simply define three variables.  They don't do anything else
and there is no hidden magic that happens when these variables are
assigned.

> I checked the PDF file and did not find any description like
> {module}_type/{module}_target rule. My question is whether there is
> an implicit rule that make cmd will try to find
> {module}_type/{module}_target variables according to defined modules?

No, there is no implicit rule that does anything like that that is part
of GNU make itself.

It's entirely possible that your makefiles define such implicit rules.
But of course we cannot know that, since we don't know what your
makefiles contain.  You will have to look into them and see where such
rules are defined and what they do.