---
name: "X11::Protocol::Ext::MIT_SUNDRY_NONSTANDARD"
section: "3pm"
platform: "linux"
package: "perl-x11-protocol-other"
version: "31-6"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/X11::Protocol::Ext::MIT_SUNDRY_NONSTANDARD"
---

# X11::Protocol::Ext::MIT\_SUNDRY\_NONSTANDARD(3pm)

X11R2/R3 compatibility mode

## NAME

X11::Protocol::Ext::MIT\_SUNDRY\_NONSTANDARD - X11R2/R3 compatibility mode

## SYNOPSIS

```
 use X11::Protocol;
 my $X = X11::Protocol->new;
 $X->init_extension('MIT-SUNDRY-NONSTANDARD')
   or print "MIT-SUNDRY-NONSTANDARD extension not available";
```

## DESCRIPTION

The MIT-SUNDRY-NONSTANDARD extension controls a "bug mode" setting in the server which helps some X11R2 and X11R3 client programs, including `"xterm"` from those releases.

Bug mode means: relaxing event mask checking in grab pointer and button requests and window do-not-propagate attributes (to ignore mask bits which are not applicable); something for non-overlapping sibling window stacking order; and keeping maximum keycode below 255 to avoid an Xt toolkit segfault.  Unless working with old client programs then these things are unlikely to be of interest.

## REQUESTS

The following are made available with an `init_extension()` per "EXTENSIONS" in X11::Protocol.

```
    my $bool = $X->init_extension('MIT-SUNDRY-NONSTANDARD');
```

- "$X-\>MitSundryNonstandardSetBugMode ($flag)"

  - "$flag = $X-\>MitSundryNonstandardGetBugMode ()"

  Get or set the bug mode flag.  1 means compatibility mode is on, 0 means off.

## SEE ALSO

X11::Protocol

[**xset**(1)](/xset/1.md) "bc" option to control the bug flag from the command line.

[**Xserver**(1)](/Xserver/1.md) "bc" command-line option to set the flag at server startup.

## HOME PAGE

\<http://user42.tuxfamily.org/x11-protocol-other/index.html\>

## LICENSE

Copyright 2011, 2012, 2013, 2014, 2017 Kevin Ryde

X11-Protocol-Other is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

X11-Protocol-Other is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with X11-Protocol-Other.  If not, see \<http://www.gnu.org/licenses/\>.