Volume 6A: Motif Programming Manual

not been specified, the default source icon for the Screen object is used.

At any point during a drag, the initiating client can call XmDragCancel() to cancel the transfer. The user can also

cancel the operation by pressing the ESCAPE key. The initiating client can retrieve additional information about the

current drop site by calling XmDropSiteRetrieve() during the drag.

After the user drops the data in a drop site, the drag source has one last chance to check the status of the transfer and

provide custom visual effects. After the receiving client's XmN-dropProc completes, the DragContext's

XmN-dropStartCallback is invoked. This routine has a callback structure of type

XmDropStartCallbackStruct, which is defined as follows:

typedef struct {

int reason;

XEvent *event;

Time timeStamp;

unsigned char operation;

unsigned char operations;

unsigned char dropSiteStatus;

unsigned char dropAction;

Position x;

Position y;

} XmDropStartCallbackStruct, *XmDropStartCallback;

The reason field is set to XmCR_DROP_START, while the operation, operations, and dropSiteStatus

fields are set as described previously. The dropAction field is set to XmDROP if the user has simply dropped the

data, XmDROP_HELP if the user has requested help on the drop site, or XmDROP_CANCEL if the user has cancelled

the transfer.

19.4.6 Cleaning Up

The initiating client can also register callbacks that are invoked after a drag and drop transfer has completed. The

XmN-dropFinishCallback is called after the receiver's XmN-transferProc ...