Re: intermediate files

[Eli Zaretskii]

> Date: Sun, 24 Oct 2010 02:19:50 -0800
> From: ali hagigat <address@hidden>
> 
> The first difference is what happens if the intermediate file does not
> exist. If an ordinary
> file b does not exist, and make considers a target that depends on b,
> it invariably creates b
> and then updates the target from b. But if b is an intermediate file,
> then make can leave well
> enough alone. It won’t bother updating b, or the ultimate target,
> unless some prerequisite
> of b is newer than that target or there is some other reason to update
> that target.
> ------------------------------------------------------------------------------------------------------
> "...can leave well enough alone..", Who is alone?

This is a frequently used English idiom.  "Leave something alone"
means not to touch it in any way.  In this case, it means Make will
not try to create B if it is an intermediate file that does not exist.

> by the way it
> won't bother updating b or it won't update b!!, because understanding
> the word 'bother' is another barrier I think in this critical moment
> of understanding the logic!

It won't update it.  Again, "won't bother doing something" means
"won't do it".

> But why in the result of our example, we have: "cp my.c.in my.c" or
> my.c has been updated!!

Because in this case Make needs my.c to create my.o.  my.o is _not_ an
intermediate file.  This is explained in the following part of the
manual which you cited:

  It won’t bother updating b, or the ultimate target, unless some
  prerequisite of b is newer than that target or there is some other
  reason to update that target.

Note the last part: "or there is some other reason".  In this case,
the reason is that my.c is needed to get to my.o.