BadAccess to a GrabButton

[Sam Varshavchik]

On Mon, May 4, 2020 at 3:57 AM Walter Harms <wharms at bfs.de>
wrote:
>
> Hi  Sam Varshavchik,
> could you please elaborate a bit what you are doing exactly ?
> Someone should be able to replicate that you are doing.
>
> You have a (simple) programm you can share ?
> Even pseudo code would be ok.

I'm working on my own X11-based widget library because ...that's what
I do in my free time. For that reason, the entire code dump of
https://www.libcxx.org/w/ is not likely to work here.

I was just hoping anyone would know off the top of their head of any
other reason I might get a BadAccess response to a GrabButton, other
than the only reason described in the X11 specs. The only reason I
could find there was a conflicting grab, but according to x11trace I
was ungrabbing the button before grabbing it again.

In the meantime, for other reasons I had to reorder some of the event
handling in my library, and that made the error disappear. From what I
can tell, this sequence of events is identical:

000:<:0533: 24: Request(28): GrabButton owner-events=false(0x00)
grab-window=0x03200003
event-mask=ButtonPress,ButtonRelease,EnterWindow,LeaveWindow,PointerMotion
pointer-mode=Synchronous(0x00) keyboard-mode=Synchronous(0x00)
confine-to=None(0x00000000) cursor=None(0x00000000) button=any
button(0x00) modifiers=AnyModifier
000:<:06a7: 24: Request(28): GrabButton owner-events=false(0x00)
grab-window=0x0320004d
event-mask=ButtonPress,ButtonRelease,EnterWindow,LeaveWindow,PointerMotion
pointer-mode=Synchronous(0x00) keyboard-mode=Synchronous(0x00)
confine-to=None(0x00000000) cursor=None(0x00000000) button=any
button(0x00) modifiers=AnyModifier
000:<:06d8: 12: Request(29): UngrabButton button=any button(0x00)
grab-window=0x0320004d modifiers=AnyModifier
000:<:09f3: 24: Request(28): GrabButton owner-events=false(0x00)
grab-window=0x0320004d
event-mask=ButtonPress,ButtonRelease,EnterWindow,LeaveWindow,PointerMotion
pointer-mode=Synchronous(0x00) keyboard-mode=Synchronous(0x00)
confine-to=None(0x00000000) cursor=None(0x00000000) button=any
button(0x00) modifiers=AnyModifier
000:<:0a0a: 12: Request(29): UngrabButton button=any button(0x00)
grab-window=0x0320004d modifiers=AnyModifier
000:<:0a0d: 12: Request(29): UngrabButton button=any button(0x00)
grab-window=0x03200003 modifiers=AnyModifier

For grab-window=0x0320004d there's a grab, an ungrab, grab again, and
ungrab. Same as last time. Although the other events are different,
based on my read of the specs only other grabs should matter here, and
nothing else.