Re: some questions about GNU make

[ali hagigat]

To this end, after reading in all makefiles, make will consider each as
a goal target and
attempt to update it. If a makefile has a rule which says how to update
it (found either
in that very makefile or in another one) or if an implicit rule applies
to it (see Chapter 10
[Using Implicit Rules], page 101), it will be updated if necessary.
After all makefiles have
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Sam,

Thank you to reply. But I did not understand what the manual says!! I
copied the lines again.

It says: " make will consider each as a goal target.."
Will consider what? Each makefile? as far as I know a makefile tries
to update a default goal file by running its commands. Where is the
commands and rules for these makefiles? What does "updating a
makefile" mean? How it is related to RCS and SCCS files?

"If a makefile has a rule which says how to update it (found either in
that very makefile)..."

Can a makefile update itself by its own rule? Can you write a simple
makefile to do it? I am looking for an example for the following
section of GNU make manual:

3.7 How Makefiles Are Remade

It has been written very ambiguous and it is not clear.



On Sat, Aug 14, 2010 at 4:33 PM, Sam Ravnborg <address@hidden> wrote:
>
> On Sat, Aug 14, 2010 at 04:10:38PM +0430, ali hagigat wrote:
> > 3.7 How Makefiles Are Remade
> > Sometimes makefiles can be remade from other files, such as RCS or SCCS files.
> > If a makefile can be remade from other files, you probably want make to get an
> > up-to-date version of the makefile to read in.
> > To this end, after reading in all makefiles, make will consider each as a
> > goal target and
> > attempt to update it. If a makefile has a rule which says how to update it
> > (found either
> > in that very makefile or in another one) or if an implicit rule applies to it
> > (see Chapter 10
> > [Using Implicit Rules], page 101), it will be updated if necessary. After
> > all makefiles have been checked, if any have actually been changed, make
> > starts with a clean slate and reads all the makefiles over again. (It will
> > also attempt to update each of them over again, but normally this will not
> > change them again, since they are already up to date.)
> > --------------------------------------------------------------------------------------------
> > I have copied some lines from the manual GNU make and have some questions.
> > What are RCS and SCCS files? Where are they?
>
> RCS:
> http://en.wikipedia.org/wiki/Revision_Control_System
> SCCS:
> http://en.wikipedia.org/wiki/Source_Code_Control_System
>
> > make will consider each Makefile as a goal target? What makefiles is it
> > talking about? the makefiles that have been included?
> Please have a look at "Including Other Makefiles"
>
> Also if you cared to explain the background for your
> question we could maybe help you.
>
>        Sam