Re: How does one find out what file a library has been loaded from?

[Alan Mackenzie]

Hello, Eli.

On Tue, Jul 19, 2022 at 15:39:11 +0300, Eli Zaretskii wrote:
> > Date: Tue, 19 Jul 2022 10:52:08 +0000
> > From: Alan Mackenzie <acm@muc.de>

> > Hello, Emacs.

> > Forgive me if I've asked this before, but how does one determine what
> > file a library has been loaded from?  In particular, whether that file
> > is a source file, a byte compiled file or a native compiled file.

> > I've tried looking at load-history, and it tells me cc-engine was loaded
> > from 

> >   "/home/acm/emacs/emacs.git/sub-master-5/lisp/progmodes/cc-engine.elc"

> > ..  I think that's a lie.  I suspect I'm dealing with a native compiled
> > cc-engine, here.  In fact, the string ".eln" doesn't occur anywhere in
> > load-history, and I _know_ some of the files are native compiled - my
> > build was configured with-native-compilation.

> > So, how do I find this out?

> What do you like to find? whether it was loaded from cc-engine.elc or
> cc-engine-XXXXXX.eln?

Exactly that, yes.

> If so, why does it matter?

It matters a great deal.  There's the purely philosophical point that one
should be able to control and understand ones own Emacs.  A further point
is that Emacs should not deceive its users.

There's the point that if you're doing benchmark timings, the results are
meaningless if you don't know what you're timing.

The reason I asked was I was seeing a bug in what I suspected to be a
..eln, but didn't see it in .elc's, and thus suspected a native compiler
bug.  I've seen other things since, and don't suspect that any more.

But I'd still like to be able to know what file I'm executing.

-- 
Alan Mackenzie (Nuremberg, Germany).