Grabbing screen concurrently crashes with Linux.

[mihaiparvu]

General information:

• OS name: Debian GNU/Linux (VirtualBox)
• OS version: 10
• OS architecture: 64 bits
• Resolutions:
  • Monitor 1: 800x600
• Python version: 3.7.3
• MSS version: 5.1.0

For GNU/Linux users:

• Display server protocol and version, if known: X server
• Desktop Environment: XFCE 4
• Composite Window Manager name and version: Cairo v1.14.6

Description of the warning/error

Grabbing screen concurrently by using threads crashes mss when running with Linux.

Code to reproduce:

import time
import threading

from mss import mss


# record for one second
def record():
    start_time = time.time()
    while time.time() - start_time < 1:
        with mss() as sct:
            sct.grab(sct.monitors[1])


t1 = threading.Thread(target=record)
t2 = threading.Thread(target=record)

t1.start()
time.sleep(0.5)
t2.start()

Full message

[xcb] Unknown sequence number while processing reply
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python3: ../../src/xcb_io.c:643: _XReply: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Aborted

Other details

This is working fine under Windows (5.1.0) and when running with Linux and using and older mss version (4.0.3).

[BoboTiG]

Hey,

Sorry for the long delay. Thank you for the report, it will be fixed ASAP :)

[mihaiparvu]

No worries. Thanks for the fix and your great work!