Newsgroups: comp.windows.x
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!bloom-beacon!dont-send-mail-to-path-lines
From: doug@genmri.UUCP (Doug Becker)
Subject: Re: XGetImage on Sun XServer
Message-ID: <9104050318.AA18793@genmri.sane.COM>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
References: <9104042219.AA05949@sun.Eng.Sun.COM>
Date: 5 Apr 91 03:17:43 GMT
Lines: 23

    The problem is, once x_offset and
    y_offset reach > 1280x1056, XGetImage continually returns NULL.

It's only a hunch, but I'll bet this is a memory-related problem.  In
particular, perhaps one of the following is happening:

The server is unable to ALLOCATE_LOCAL a hunk of memory and returns
BadAlloc to _XReply, which returns status 0 (error) to XGetImage, which
returns NULL to you.  Interestingly, Alloc is not listed as one of the
possible errors for the GetImage request, although the GetImage request
seems capable of generating it (R4: mit/server/dix/dispatch.c, line 1952).

The server returns the image successfully, but Xlib is unable to Xcalloc an
XImage to return to you, so XCreateImage returns NULL to XGetImage, which
passes the NULL pointer on to you.

Try freeing up some memory to see if this is indeed the case.

-- 

Doug Becker
doug@nmri.ge.com
crdgw1!sane!doug