XmDropTransfer(library call) XmDropTransfer(library call)

NAME

XmDropTransfer -- The DropTransfer widget class

SYNOPSIS

#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
procedure of type XtSelectionCallbackProc that delivers the requested
selection 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 initiated 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;

client_data
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
programmer 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 | XmDropTransferEntryRec * | NULL | CG |
+--------------------+---------------------+--------------------------+--------------------+--------+
|XmNincremental | XmCIncremental | Boolean | False | CSG |
+--------------------+---------------------+--------------------------+--------------------+--------+
|XmNnumDropTransfers | XmCNumDropTransfers | Cardinal | 0 | CSG |
+--------------------+---------------------+--------------------------+--------------------+--------+
|XmNtransferProc | XmCTransferProc | XtSelectionCallbackProc | NULL | CSG |
+--------------------+---------------------+--------------------------+--------------------+--------+
|XmNtransferStatus | XmCTransferStatus | unsigned 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 Interface. 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 complete. 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 selection atom passed is _MOTIF_DROP. For
additional information on selection callback procedures,
see X Toolkit Intrinsics--C Language 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

XmTRANSFER_SUCCESS
The transfer succeeded.

XmTRANSFER_FAILURE
The transfer failed.

Inherited Resources

DropTransfer inherits behavior and a resource from Object. For a
complete description of this resource, refer to the Object reference
page.

+---------------------------------------------------------------------+
| Object Resource Set |
|Name | Class | Type | Default | Access |
+-------------------+-------------+----------------+---------+--------+
|XmNdestroyCallback | XmCCallback | XtCallbackList | NULL | C |
+-------------------+-------------+----------------+---------+--------+
+-------------------+-------------+----------------+---------+--------+

RELATED INFORMATION

Object(3), XmDisplay(3), XmDragContext(3), XmDragIcon(3),
XmDropSite(3), XmDropTransferAdd(3), and XmDropTransferStart(3).

XmDropTransfer(library call)