Add a few comments to ProcXGrabDevice.

1 files changed, 12 insertions, 1 deletions

diff --git a/Xi/grabdev.c b/Xi/grabdev.c
index f3349ba8c..f2227bcf1 100644
--- a/Xi/grabdev.c
+++ b/Xi/grabdev.c
@@ -160,8 +160,19 @@ ProcXGrabDevice(ClientPtr client)
  * get the device. Then run through all available event indices (those are
  * set when XI starts up) and binary OR's the device's mask to whatever the
  * event mask for the given event type was. 
+ * If an error occurs, it is sent to the client. Errors are generated if 
+ *  - if the device given in the event classs is invalid
+ *  - if the device in the class list is not the device given as parameter (no
+ *  error if parameter is NULL)
  *
  * mask has to be size EMASKSIZE and pre-allocated.
+ *
+ * @param client The client to send the error to (if one occurs)
+ * @param list List of event classes as sent from the client.
+ * @param count Number of elements in list.
+ * @param mask Preallocated mask (size EMASKSIZE).
+ * @param dev The device we're creating masks for.
+ * @param req The request we're processing. Used to fill in error fields.
  */
 
 int
@@ -179,7 +190,7 @@ CreateMaskFromList(ClientPtr client, XEventClass * list, int count,
 
     for (i = 0; i < count; i++, list++) {
 	device = *list >> 8;
-	if (device > 255) {
+	if (device > 255) { /* FIXME: we only use 7 bit for devices? */
 	    SendErrorToClient(client, IReqCode, req, 0, BadClass);
 	    return BadClass;
 	}