| Title: | DECWINDOWS 26-JAN-89 to 29-NOV-90 |
| Notice: | See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit |
| Moderator: | STAR::VATNE |
| Created: | Mon Oct 30 1989 |
| Last Modified: | Mon Dec 31 1990 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 3726 |
| Total number of notes: | 19516 |
Questions about the allocation of Pixmaps
I want to allocate a pixmap with given width and height, using the
XCreatePixmap function. This pixmap is supposed to be allocated
into the off-screen memory managed by the server.
What happens if the off-screen memory is not large enough (too many
pixmaps have already been created, or the size of my pixmap is to
important for the available memory) ? I have been told that the
pixmap is then placed into the memory of the station, or on disk.
Is it correct ?, and what happens if I am on a X Terminal, without
disk ?.
Is it possible to test the available memory before making my request
to XCreatePixmap?
Many thanks
Maya
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 2841.1 | STAR::KLEINSORGE | Fred Kleinsorge, VMS Development | Thu May 31 1990 12:55 | 15 | |
Nope. Not even as a hint. The asynchronous connection between the
client and server would make any such inquiry inherently unreliable.
What happens is that your PIXMAP will be loaded into offscreen memory
(if there is such a thing) in a server dependent fashion. This may
cause other PIXMAPs to be: Swapped to main memory, written to disk,
thrown away completely. Or, your request may simply fail. It all
really depends on the server and to some extent the hardware. And
even knowing the total "offscreen memory" can't tell you if your
PIXMAP would fit - since you also would need to know things about
offscreen memory organization, server design (for the specific server)
and offscreen memory fragmentation.
| |||||
| 2841.2 | DECWIN::FISHER | Prune Juice: A Warrior's Drink! | Thu May 31 1990 18:55 | 11 | |
On DEC VMS servers, you can allocate pixmaps up to a certain absolute size (roughly the size of the screen on a GPX, for example). If your pixmaps don't all fit in, they are swapped to server's process virtual memory. I don't know of any case where a pixmap is arbitrarily thrown away. That would be a violation of the X protocol. To find out you have to allocate it. Do an XSync, establish an error handler, do the alloc, do another XSync. If the error handler was not called, the pixmap was allocated successfully. Burns | |||||