Volume 6A: Motif Programming Manual

The Display object provides two resources that can be set to indicate which protocol the toolkit should use when an

application is the initiating or the receiving application in a drag and drop transfer. These resources are

XmN-dragInitiatorProtocolStyle and XmN-dragReceiverProtocolStyle. An application can set

the resources if it needs to specify a particular protocol, or they can be set by the user in a resource file. We describe

the different values for the resources and how the actual protocols are determined in Section #sdragprot, when we

discuss how to customize drag and drop. The protocol that is used to transfer data when the drop occurs encompasses

the Xt incremental and non−incremental selection protocols. The DropTransfer object created by the receiving

application handles the drop protocol. When the DropTransfer object is created using XmDropTransferStart(),

the receiver specifies resources that indicate the list of desired targets, as well as an XmNtransferProc that

handles the data once it has been converted by the initiator. The toolkit processes the requests one at a time by calling

the -XmNconvertProc of the initiating client. This procedure processes the request and passes the data back to the

XmN-transferProc.

The DragContext and DropTransfer objects both have XmN-incremental resources that specify whether or not the

data transfer is incremental. Incremental transfers are used when the data is too large for a single X protocol request.

No matter how the two resources are ...