is there a way to check programmatically (via ioctl(), etc.) or by reading a file in /sys, /proc or /dev) whether the screen has been blanked by the Linux console screensaver?
Thanks and best regards,
Günter
Okay, checked the xset source code . The relevant code parts are
#include <X11/extensions/dpms.h>
...
Display* dpy = XOpenDisplay(NULL);
...
int dummy;
CARD16 standby, suspend, off;
BOOL onoff;
CARD16 state;
printf("DPMS (Energy Star):\n");
if (DPMSQueryExtension(dpy, &dummy, &dummy))
{
if (DPMSCapable(dpy))
{
DPMSGetTimeouts(dpy, &standby, &suspend, &off);
printf (" Standby: %d Suspend: %d Off: %d\n",
standby, suspend, off);
DPMSInfo(dpy, &state, &onoff);
if (onoff)
{
printf(" DPMS is Enabled\n");
switch (state)
{
case DPMSModeOn:
printf(" Monitor is On\n");
break;
case DPMSModeStandby:
printf(" Monitor is in Standby\n");
break;
case DPMSModeSuspend:
printf(" Monitor is in Suspend\n");
break;
case DPMSModeOff:
printf(" Monitor is Off\n");
break;
default:
printf(" Unrecognized response from server\n");
}
}
}
}
Just in case anyone else needs this ;-)
You can parse the output of xset q
with DISPLAY
set, but it's not pretty.
$ xset q
Keyboard Control:
auto repeat: on key click percent: 0 LED mask: 00000000
XKB indicators:
00: Caps Lock: off 01: Num Lock: off 02: Scroll Lock: off
03: Compose: off 04: Kana: off 05: Sleep: off
06: Suspend: off 07: Mute: off 08: Misc: off
09: Mail: off 10: Charging: off 11: Shift Lock: off
12: Group 2: off 13: Mouse Keys: off
auto repeat delay: 250 repeat rate: 30
auto repeating keys: 00ffffffdffffbbf
fadfffefffedffff
9fffffffffffffff
fff7ffffffffffff
bell percent: 50 bell pitch: 400 bell duration: 100
Pointer Control:
acceleration: 20/10 threshold: 4
Screen Saver:
prefer blanking: yes allow exposures: yes
timeout: 0 cycle: 600
Colors:
default colormap: 0x20 BlackPixel: 0 WhitePixel: 16777215
Font Path:
/usr/share/fonts/misc,/usr/share/fonts/100dpi:unscaled,/usr/share/fonts/75dpi:unscaled,/usr/share/fonts/TTF,/usr/share/fonts/Type1,/usr/share/fonts/misc/,/usr/share/fonts/TTF/,/usr/share/fonts/Type1/,/usr/share/fonts/100dpi/,/usr/share/fonts/75dpi/,built-ins
DPMS (Energy Star):
Standby: 1200 Suspend: 1800 Off: 0
DPMS is Enabled
Monitor is On
Font cache:
Server does not have the FontCache Extension
I made an equivalent implementation of Günter's code in Python with ctypes.
import ctypes
import struct
ctypes.cdll.LoadLibrary('libXext.so')
libXext = ctypes.CDLL('libXext.so')
DPMSFAIL = -1
DPMSModeOn = 0
DPMSModeStandby = 1
DPMSModeSuspend = 2
DPMSModeOff = 3
def get_DPMS_state(display_name_in_byte_string=b':0'):
state = DPMSFAIL
if not isinstance(display_name_in_byte_string, bytes):
raise TypeError
display_name = ctypes.c_char_p()
display_name.value = display_name_in_byte_string
libXext.XOpenDisplay.restype = ctypes.c_void_p
display = ctypes.c_void_p(libXext.XOpenDisplay(display_name))
dummy1_i_p = ctypes.create_string_buffer(8)
dummy2_i_p = ctypes.create_string_buffer(8)
if display.value:
if libXext.DPMSQueryExtension(display, dummy1_i_p, dummy2_i_p)\
and libXext.DPMSCapable(display):
onoff_p = ctypes.create_string_buffer(1)
state_p = ctypes.create_string_buffer(2)
if libXext.DPMSInfo(display, state_p, onoff_p):
onoff = struct.unpack('B', onoff_p.raw)[0]
if onoff:
state = struct.unpack('H', state_p.raw)[0]
libXext.XCloseDisplay(display)
return state
Calling sample is on my github .
I haven't done any desktop development in ages, but memory tells me that most linux screensavers were being executed by xscreensaver - maybe checking whether the process is running, or going through its source-code to see for any system-state being set, or asking on the project maillist would yield some results. Of course KDE and Gnome might have separate screensaver implementations by now - there is very little uniformity when it comes to linux GUIs, unfortunately...
I'm using this script to read DPMS info. It works great! Its written in PHP, but you can see the idea how it works.
<?php
if ( !$pid = exec('pidof X') )
return !trigger_error(E_USER_WARNING,'Could not find pid of X');
if ( !$data = file_get_contents("/proc/$pid/cmdline") )
return !trigger_error(E_USER_WARNING,"Cound not read pid info (/proc/$pid/cmdline)");
$data = explode(chr(0),$data);
foreach($data as $key => $line) {
if ( $line == "-auth" ) {
$auth = $data[$key+1];
break;
}
}
if ( !isset($auth) )
return !trigger_error(E_USER_WARNING,'Could not find XAUTHORITY in xinit process environment');
echo exec("export DISPLAY=:0; export XAUTHORITY={$auth}; export PATH=\${PATH}:/usr/X11R6/bin; xset -q | grep \"Monitor is\" | awk '{print $3}'");
?>
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.