bug#55870: GNU Emacs 26.3, Select All(C-x h) does not work

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

>> None in particular: we store the clipboard data locally, and other
>> programs request different selection "targets" from Emacs depending on
>> the coding system they want it in.
>
> So the memory growth in the OP's scenario is due to something we do
> locally?  Where's the code which "stores the clipboard data locally"?

xselect.c.  Look at the code which changes terminal->Vselection_alist in
x_own_selection.

> Or maybe some external program does request the clipboard data on OP's
> machine?  Is there a way to know when that happens, and specifically
> to know which data-type is being requested?

The best way is to build xselect.c with TRACE_SELECTION defined to 1 in
that file.  Otherwise, tracing each of the functions in
selection-converter-alist should work too, but will not catch requests
for types Emacs does not know how to handle.