Re: [Groff] autoconf and autoreconf

[Bernd Warken]

> Von: "Bernd Warken" <address@hidden>
> > Von: "Werner LEMBERG" <address@hidden>
> >
> > > I ran `autoconf'.  There was a subdirectory `autom4te.cache/'
> > > created.  First I just deleted it.
> >
> > This directory and its contents is *always* intermediate!  It just
> > speeds up the execution of the autoconf tools.  Actually, the
> > `configure' script itself shouldn't be stored in the repository but
> > generated during a `make tarball' call...
> >
> > Please remove it again.
>
> I cannot get it away.  I tried it about 10-times.  But each update
> of groff CVS on my computer adds each time another subdirectory
> `autom4te.cache/'.
>

The wesite

http://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Autom4te-Cache.html

says the following:

#####

20.6 What is autom4te.cache?

     What is this directory autom4te.cache?  Can I safely remove it?

In the GNU Build System, configure.ac plays a central role and is read by many 
tools: autoconf to create configure, autoheader to create config.h.in, automake 
to create Makefile.in, autoscan to check the completeness of configure.ac, 
autoreconf to check the GNU Build System components that are used. To “read 
configure.ac” actually means to compile it with M4, which can be a long process 
for complex configure.ac.

This is why all these tools, instead of running directly M4, invoke autom4te 
(see autom4te Invocation) which, while answering to a specific demand, stores 
additional information in autom4te.cache for future runs. For instance, if you 
run autoconf, behind the scenes, autom4te also stores information for the other 
tools, so that when you invoke autoheader or automake etc., reprocessing 
configure.ac is not needed. The speed up is frequently 30%, and is increasing 
with the size of configure.ac.

But it is and remains being simply a cache: you can safely remove it.


     Can I permanently get rid of it?

The creation of this cache can be disabled from ~/.autom4te.cfg, see 
Customizing autom4te, for more details. You should be aware that disabling the 
cache slows down the Autoconf test suite by 40%. The more GNU Build System 
components are used, the more the cache is useful; for instance running 
‘autoreconf -f’ on the Core Utilities is twice slower without the cache 
although --force implies that the cache is not fully exploited, and eight times 
slower than without --force.

#####

So it seems to be not as bad as it seemed to be.  It can be kept for further 
runs of `autotools', for example if someone will do `automake'.

Bernd Warken