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XShm(3)				  X FUNCTIONS			       XShm(3)

       XShmQueryExtension,   XShmQueryVersion,	XShmPixmapFormat,  XShmAttach,
       XShmDetach  XShmCreateImage,   XShmPutImage,   XShmGetImage,   XShmCre-
       atePixmap, XShmGetEventBase - X Shared Memory extension functions

       #include	<X11/Xlib.h>
       #include	<sys/ipc.h>
       #include	<sys/shm.h>
       #include	<X11/extensions/XShm.h>

       Bool XShmQueryExtension(
	    Display *display);

       Bool XShmQueryVersion(
	    Display *display;
	    int	*major,	*minor;
	    Bool *pixmaps);

       int XShmPixmapFormat(
	    Display *display);

       Bool XShmAttach(
	    Display *display;
	    XShmSegmentInfo *shminfo);

       Bool XShmDetach(
	    Display *display;
	    XShmSegmentInfo *shminfo);

       XImage *XShmCreateImage (
	    Display *display;
	    Visual *visual;
	    unsigned int depth;
	    int	format;
	    char *data;
	    XShmSegmentInfo *shminfo;
	    unsigned int width,	height);

       Bool XShmPutImage(
	    Display *display;
	    Drawable d;
	    GC gc;
	    XImage *image;
	    int	src_x, src_y, dest_x, dest_y;
	    unsigned int width,	height;
	    bool send_event);

       Bool XShmGetImage (
	    Display *display;
	    Drawable d;
	    XImage *image;
	    int	x, y;
	    unsigned long plane_mask);

       Pixmap XShmCreatePixmap(
	       Display *display;
	       Drawable	d;
	       char *data;
	    XShmSegmentInfo *shminfo;
	    unsigned int width,	height,	depth);

       Status XShmGetEventBase(
	    Display *display);

       typedef struct {
	   int type;		   /* of event */
	   unsigned long serial;   /* #	of last	request	processed by server*/
	   Bool	send_event;	   /* true if this came	from a SendEvent request*/
	   Display *display;	   /* Display the event	was read from */
	   Drawable drawable;	   /* drawable of request */
	   int major_code;	   /* ShmReqCode */
	   int minor_code;	   /* X_ShmPutImage */
	   ShmSeg shmseg;	   /* the ShmSeg used in the request*/
	   unsigned long offset;   /* the offset into ShmSeg used in the request*/
       } XShmCompletionEvent;

       a structure of type XShmSegmentInfo :

       typedef struct {
	   ShmSeg shmseg;      /* resource id */
	   int shmid;	       /* kernel id */
	   char	*shmaddr;      /* address in client */
	   Bool	readOnly;      /* how the server should	attach it */
       } XShmSegmentInfo;

       XShmQueryExtension  checks  to  see if the shared memory	extensions are
       available for the specified display.

       XShmQueryVersion	returns	the version numbers of the extension implemen-
       tation. Shared memory pixmaps are supported if the pixmaps argument re-
       turns true.

       XShmAttach tells	the server to attach to	your shared memory segment. If
       all  goes well, you will	get a non-zero status, back and	your XImage is
       ready for use.

       XShmDetach tells	the server to detach from your shared memory segment.

       XShmPutImage combines an	image in memory	with a shape of	the  specified
       drawable.  If  XYBitmap	format	is  used,  the depth must be one, or a
       ``BadMatch'' error results. The foreground pixel	in the GC defines  the
       source  for the one bits	in the image, and the background pixel defines
       the source for the zero bits. For XYPixmap and ZPixmap, the depth  must
       match the depth of the drawable,	or a ``BadMatch'' error	results.

       XShmGetImage reads image	data into a shared memory XImage where display
       is the display of interest, drawable is the source drawable,  image  is
       the  destination	 XImage,  x and	y are offsets within the drawable, and
       plane_mask defines which	planes are to be read.

       XShmCreateImage allocates the memory needed for an XImage structure for
       the specified display but does not allocate space for the image itself.

       XShmPixmapFormat	 gets  the  format for the server. If your application
       can deal	with the server	pixmap data format, a  shared  memory  segment
       and shminfo structure are created.

       XShmCreatePixmap	 points	to a pixmap which you can manipulate in	all of
       the usual ways, with the	added bonus of being able to edit its contents
       directly	through	the shared memory segment.

       XShmGetEventBase	gets the completion event value.

       MIT-SHM - The MIT Shared	Memory Extension

X Version 11			 libXext 1.3.4			       XShm(3)


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