So I started working with SFML for a personal project and ran into a weird issue with SFML and controlling the rendering in a second thread. I get random crashes from X and/or xcb, usually involving an unknown request in the queue or a request in the queue during a dequeue.
Using the current build of SFML from git (as of 9:55pm PDT) on master branch. Using Linux Mint 14 with all packages updated and kernel 3.5.0-17-generic.
build command is
g++ src/engine.cpp -Wall -std=c++0x -o3 -lsfml-graphics -lsfml-window -lsfml-system -o build/engine
This is the trimmed down version which causes the problems:
#include <SFML/Graphics.hpp>
void renderThread_entry(sf::RenderWindow* window)
{
while (window->isOpen())
{
window->clear();
window->display();
}
}
int main()
{
sf::RenderWindow window(sf::VideoMode(800, 600), "XCB Error Test");
window.setActive(false);
sf::Thread renderThread(&renderThread_entry, &window);
renderThread.launch();
while (window.isOpen())
{
sf::Event event;
if (window.waitEvent(event))
{
if (event.type == sf::Event::Closed)
{
window.close();
}
}
}
renderThread.wait();
return 0;
}
Commenting out all the event stuff in the main function stops the random crashing. Add a sleep timer to the drawing thread to show that it doesn't happen on program start, but rather after a random period of time.
Some of the specific errors I get.
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
engine: ../../src/xcb_io.c:179: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
Aborted
[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0.0"
after 1900 requests (1900 known processed) with 1 events remaining.
engine: ../../src/xcb_io.c:179: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
Aborted
X Error of failed request: BadIDChoice (invalid resource ID chosen for this connection)
Major opcode of failed request: 139 (XFIXES)
Minor opcode of failed request: 5 (XFixesCreateRegion)
Resource id in failed request: 0x3e00064
Serial number of failed request: 435
Current serial number in output stream: 436
Again, these are "random" crashes in that they happen after a random period of time. If it doesn't crash right away, either wait a bit or close it and try running again.
Thanks for the help.
