XmDropTransfer(Xm) 6 January 1993 XmDropTransfer(Xm) Name XmDropTransfer - the DropTransfer widget class Syntax #include <Xm/DragDrop.h> Description DropTransfer provides a set of resources that identifies the procedures and associated information required by the toolkit in order to process and complete a drop transaction. Clients should not explicitly create a DropTransfer widget. Instead, a client initiates a transfer by calling XmDropTransferStart, which initializes and returns a DropTransfer widget. If this function is called within an XmNdropProc callback, the actual transfers are initiated after the callback returns. Even if no data needs to be transferred, XmDropTransferStart needs to be called (typically with no arguments, or just setting XmNtransferStatus) to finish the drag and drop transaction. The XmNdropTransfers resource specifies a transfer list that describes the requested target types for the source data. A transfer list is an array of XmDropTransferEntryRec structures, each of which identifies a target type. The transfer list is analogous to the MULTIPLE selections capability defined in the Inter-Client Communication Conventions Manual (ICCCM). The DropTransfer resource, XmNtransferProc, specifies a transfer pro- cedure of type XtSelectionCallbackProc that delivers the requested selec- tion data. This procedure operates in conjunction with the underlying Xt selection capabilities and is called for each target in the transfer list. Additional target types can be requested after a transfer is ini- tiated by calling the XmDropTransferAdd function. Structures An XmDropTransferEntry is a pointer to the following structure of type XmDropTransferEntryRec, which identifies a selection target associated with a given drop transaction: typedef struct { XtPointer client_data; Atom target; } XmDropTransferEntryRec, *XmDropTransferEntry; clientdata Specifies any additional information required by this selection target. target Specifies a selection target associated with the drop operation. Classes DropTransfer inherits behavior and a resource from Object. The class pointer is xmDropTransferObjectClass. The class name is XmDropTransfer. New resources The following table defines a set of widget resources used by the pro- grammer to specify data. The programmer can also set the resource values for the inherited classes to set attributes for this widget. To reference a resource by name or by class in a .Xdefaults file, remove the ``XmN'' or ``XmC'' prefix and use the remaining letters. To specify one of the defined values for a resource in a .Xdefaults file, remove the ``Xm'' prefix and use the remaining letters (in either lowercase or uppercase, but include any underscores between words). The codes in the access column indicate if the given resource can be set at creation time (C), set by using XtSetValues (S), retrieved by using XtGetValues (G), or is not applicable (N/A). XmDropTransfer resource set ____________________________________________________________________________ Name Class Type Default Access ____________________________________________________________________________ XmNdropTransfers XmCDropTransfers XmDropTransfer- * NULL EntryRec XmNincremental XmCIncremental Boolean False CSG XmNnumDrop- XmCNumDrop- Cardinal 0 CSG Transfers Transfers XmNtransferProc XmCTransferProc XtSelection- NULL CSG CallbackProc XmNtransferStatus XmCTransferStatusunsigned char XmTRANSFER_SUCCESS CSG XmNdropTransfers Specifies the address of an array of drop transfer entry records. The drop transfer is complete when all the entries in the list have been processed. XmNincremental Specifies a Boolean value that indicates whether the transfer on the receiver side uses the Xt incremental selection transfer mechanism described in X Toolkit Intrinsics -- C Language Inter- face. If the value is True, the receiver uses incremental transfer; if the value is False, the receiver uses atomic transfer. XmNnumDropTransfers Specifies the number of entries in XmNdropTransfers. If this resource is set to 0 at any time, the transfer is considered com- plete. The value of XmNtransferStatus determines the completion handshaking process. XmNtransferProc Specifies a procedure of type XtSelectionCallbackProc that delivers the requested selection values. The widget argument passed to this procedure is the DropTransfer widget. The selec- tion atom passed is MOTIFDROP. For additional information on selection callback procedures, see Toolkit Intrinsics -- C Lan- guage Interface. XmNtransferStatus Specifies the current status of the drop transfer. The client updates this value when the transfer ends and communicates the value to the initiator. The possible values are + XmTRANSFERSUCCESS -- the transfer succeeded. + XmTRANSFERFAILURE -- the transfer failed. Inherited resources DropTransfer inherits behavior and a resource from Object. For a com- plete description of this resource, refer to the Object(Xm) reference page. Object resource set ____________________________________________________________________________ Name Class Type Default Access ____________________________________________________________________________ XmNdestroyCallback XmCCallback XtCallbackList NULL C See also Object(Xm), XmDisplay(Xm), XmDragContext(Xm), XmDragIcon(Xm), XmDropSite(Xm), XmDropTransferAdd(Xm) and XmDropTransferStart(Xm).