Re: NSTRACE: Create message indicating window and/or buffer.

[Eli Zaretskii]

> Date: Wed, 06 Sep 2017 22:07:53 -0700
> From: Keith David Bershatsky <address@hidden>
> 
> I would like to insert a NSTRACE message to let me know the window and/or 
> buffer at issue.
> 
> For example, ns_update_window_end contains a first argument of `w`.  I would 
> like to see the pretty human readable name for that window, just like what we 
> see when running `M-x trace-redisplay`.  The `%s` format argument requires a 
> `char`, and rejects a Lisp_Object.
> 
> How can I achieve this feature?

Something like this should work:

  if (BUFFERP (w->contents) && STRINGP (BVAR (XBUFFER (w->contents), name)))
    fprintf (stderr, "window %s\n", SSDATA (BVAR (XBUFFER (w->contents), name));

This prints the name of the buffer shown in the window.