Strange error message

[Leonatus]

Windows 10, 64 bit, Sigil v. 1.4.3.
Recently, at opening Sigil, I sometimes receive this error message:

Error info: Critical: ARB::createContext: wglCreateContextAttribsARB() failed (GL error code: 0x0) for format: QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat::DefaultSwapBehavior, swapInterval 1, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::NoProfile), shared context: 0x30000 (Der Vorgang wurde erfolgreich beendet.)
Sigil version: 1.4.3
Runtime Qt: 5.12.9
Compiled Qt: 5.12.9
System: Windows 10 (10.0)
Architecture: x86_64

It's not really a problem, as the book will open nevertheless, and the messages doesn't occur steadily. But it's irritating. Soemone who knows what happens there?

[KevinH]

A google search of the error message produced this:

https://bugreports.qt.io/browse/QTBUG-52397

https://bugreports.qt.io/browse/QTBUG-58322

https://www.mobileread.com/forums/sh....php?p=3951007

So it appears to be OpenGL related and Qt Related. Did you have a large number of Sigil instances open at the same time? Have you tried updating your video driver or make video driver related changes?

[KevinH]

Upon further investigation, it seems to be caused by an out of memory error when allocating memory for a shared memory space. Or by trying to allocate memory too late after initialization. I would double check my video driver then reboot my entire computer to make sure a memory leak in some application is not causing problems at the system level.

Not much of a Windows person so perhaps DiapDealer may have a better idea of what is going on here.

[DiapDealer]

I've had the error come up rarely on both Linux and Windows. And like the OP, it never seemed to cause any issues after dismissing it. I haven't encountered it in a long time (though my time spent using Sigil on Windows is rather limited these days).

[BeckyEbook]

I run into such a bug from time to time (Windows 10), but I have never caught it twice in a row. Usually, the next launch of Sigil starts the program without a problem.
I have an old computer and the "latest" drivers are 8 years old, so even if it's related to the graphics card or drivers, there's nothing I can do about it.

I remember this change in the code, but I have the feeling that I see this message on average once every two months anyway.

I do not report it because:
- I usually work on my build, which may have other issues related to my changes, so I don't want to call the guards when only my private build is on fire,
- I can't repeat it until many weeks have passed and the error message reappears.

It is difficult to debug an error that does not want to be caught.

[KevinH]

That change:

QCoreApplication::setAttribute(Qt::AA_ShareOpenGLC ontexts);

is interesting in that the backtraces attached to those Qt bug reports and others that google found showed that the specific error code 0 was associated with failures to allocate shared memory for openGL (which uses in 4 meg blocks).

So it may be related to the problem?

Kevin

Originally Posted by BeckyEbook

I run into such a bug from time to time (Windows 10), but I have never caught it twice in a row. Usually, the next launch of Sigil starts the program without a problem.
I have an old computer and the "latest" drivers are 8 years old, so even if it's related to the graphics card or drivers, there's nothing I can do about it.

I remember this change in the code, but I have the feeling that I see this message on average once every two months anyway.

I do not report it because:
- I usually work on my build, which may have other issues related to my changes, so I don't want to call the guards when only my private build is on fire,
- I can't repeat it until many weeks have passed and the error message reappears.

It is difficult to debug an error that does not want to be caught.

[BeckyEbook]

If you mean that with too little memory available in the system (or too defragmented to allocate enough space) – it is possible. I put a lot of strain on my computer, so sometimes memory is too low.

[DiapDealer]

I've played with Qt::AA_ShareOpenGLContexts in the past, but I'm fairly certain I've seen the error with and without it.

[KevinH]

Good to know.

[DiapDealer]

That said: I'm not entirely sure it's necessary. I just know I've see some suggest that it's necessary for QtWebEngine.

[Leonatus]

Originally Posted by KevinH

Did you have a large number of Sigil instances open at the same time?

No, always a single one.

Have you tried updating your video driver or make video driver related changes?

No, nothing of that kind.

[Leonatus]

Originally Posted by BeckyEbook

I run into such a bug from time to time (Windows 10), but I have never caught it twice in a row. Usually, the next launch of Sigil starts the program without a problem.
I have an old computer and the "latest" drivers are 8 years old, so even if it's related to the graphics card or drivers, there's nothing I can do about it.

That exactly, but my computer is only one year old.

[DiapDealer]

I've had it happen on brand-new hardware with the very latest drivers. I'm convinced it's a rare race condition of some kind that's causing a spurious warning, to be honest. That's on Windows, mind you.

[DNSB]

Just to toss in that I've seen that error message 3 or 4 times and it doesn't seem to cause any issues nor is it repeatable. I've seen it using the builtin display with the Intel video driver and external monitors using the Nvidia driver though a docking station.