Re: gnuclient *feature* -- crash when frames lose X connection

Michael Toomim <toomim(a)cs.berkeley.edu&gt; writes: Apparently X/Xt library makes it very hard to handle that situation sanely. When the connection to the X server gets lost, our callback function `x_IO_error_handler' is called. According to a comment in the source, "we should not return from this function, or Xlib might just decide to exit()." So what XEmacs does instead is longjump to top-level, but marks the device as "being deleted" (i.e. unusable) beforehand. The code that could get executed between that point and the point when the device is actually deleted is supposed to check for DEVICE_X_BEING_DELETED(). I've added such checks to several places I thought were suspicious, and I got the problem resolved on my setup at the time. But others kept reporting the crashes, and I was unable to fix it. Maybe you can figure out -- in a debugger -- exactly where and why XEmacs dies following the loss of connection between one of its X devices and the X server. This is idle speculation, but I suspect the problem could be that it is not sufficient to "enqueue a magic event" to get rid of the faulty device. The "next event" action might read from the dead device and die for it. Perhaps a more aggressive action needs to be taken -- say, set a variable "dead_devices_exist_p" to 1, which makes the event loop check for the state of the devices *before* trying to read any events from them.