From: Chong Yidong <cyd@stupidchicken.com>
To: emacs-devel@gnu.org
Subject: X selections and multi tty
Date: Thu, 26 May 2011 18:49:12 -0400 [thread overview]
Message-ID: <87hb8h2i3b.fsf@stupidchicken.com> (raw)
I'm doing a cleanup of xselect.c, and came across something puzzling.
AFAIU, clipboards and other X selections are per-X-server, which
corresponds to terminal objects in Emacs (or close enough; each terminal
corresponds to an X display opened by XOpenDisplay).
Emacs currently uses a global variable, Vselection_alist, to keep track
of what X selections it controls. This seems incorrect, and OTOH it
should lead to funky behavior when you use the same Emacs session on two
different X servers.
For instance, Emacs might own the clipboard on two X servers
simultaneously; when it receives a SelectionClear on one, it will act as
though it's lost the clipboard period---when in fact the second X server
still think Emacs owns the clipboard.
The obvious solution seems to be to change Vselection_alist into a
terminal-local variable. However, there exists this code in
x_handle_selection_clear:
/* If the new selection owner is also Emacs,
don't clear the new selection. */
BLOCK_INPUT;
/* Check each display on the same terminal,
to see if this Emacs job now owns the selection
through that display. */
for (t_dpyinfo = x_display_list; t_dpyinfo; t_dpyinfo = t_dpyinfo->next)
if (t_dpyinfo->terminal->kboard == dpyinfo->terminal->kboard)
{
Window owner_window
= XGetSelectionOwner (t_dpyinfo->display, selection);
if (x_window_to_frame (t_dpyinfo, owner_window) != 0)
{
UNBLOCK_INPUT;
return;
}
}
UNBLOCK_INPUT;
This contradicts what I thought: it assumes that if Emacs owns the
selection on a different display, it doesn't need to relinquish
ownership of the selection.
Anyone know what's going on?
next reply other threads:[~2011-05-26 22:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-26 22:49 Chong Yidong [this message]
2011-05-27 0:47 ` X selections and multi tty Stefan Monnier
2011-05-27 2:47 ` Chong Yidong
2011-05-27 3:43 ` Chong Yidong
2011-05-27 12:33 ` Stefan Monnier
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