XmTransferValue — A toolkit function that transfers data to a
destination
#include <Xm/Xm.h>
void XmTransferValue(
XtPointer transfer_id,
Atom target,
XtCallbackProc proc,
XtPointer client_data,
Time time);
XmTransferValue converts a selection, transferring any data from the
selection owner, in the context of an already-initiated data transfer
operation. An application can call this routine from an
XmNdestinationCallback procedure or any function called as a result.
The caller of XmTransferValue supplies the target to which
the selection is converted. The caller also supplies a callback procedure to
handle the data that results from the conversion.
- transfer_id
- Specifies a unique indentifier for the data transfer operation. The value
must be the same as the value of the transfer_id member of the
XmDestinationCallbackStruct passed to the
XmNdestinationCallback procedure.
- target
- Specifies the target to which the selection is to be converted.
- proc
- Specifies a callback procedure to be invoked when the selection has been
converted and the data, if any, is available. This procedure is
responsible for inserting or otherwise handling any data transferred. The
procedure can also terminate the data transfer by calling
XmTransferDone. The proc receives three arguments:
- •
- The widget that requested the conversion
- •
- The value of the client_data argument
- •
- A pointer to an XmSelectionCallbackStruct
-
- This procedure can be called before or after XmTransferValue
returns.
- client_data
- Specifies data to be passed to the callback procedure (the value of the
proc argument) when the selection has been converted.
- time
- Specifies the time of the XEvent that triggered the data transfer.
You should typically set this field to
XtLastTimestampProcessed.
The callback procedure (the value of the proc argument)
receives a pointer to an XmSelectionCallbackStruct, which has the
following definition:
typedef struct
{
int reason;
XEvent *event;
Atom selection;
Atom target;
Atom type;
XtPointer transfer_id;
int flags;
int remaining;
XtPointer value;
unsigned long length;
int format;
} XmSelectionCallbackStruct;
- reason
- Indicates why the callback was invoked.
- event
- Points to the XEvent that triggered the callback. It can be
NULL.
- selection
- Specifies the selection that has been converted.
- target
- Specifies the target to which XmTransferValue requested conversion.
The value is the same as the value of the target argument to
XmTransferValue.
- type
- Specifies the type of the selection value. This is not the target, but the
type used to represent the target. The value XT_CONVERT_FAIL means
that the selection owner did not respond to the conversion request within
the Intrinsics selection timeout interval.
- transfer_id
- Specifies a unique indentifier for the data transfer operation. The value
is the same as the value of the transfer_id argument to
XmTransferValue.
- flags
- This member is currently unused. The value is always
XmSELECTION_DEFAULT.
- remaining
- Indicates the number of transfers remaining for the operation specified by
transfer_id.
- value
- Represents the data transferred by this request. The application is
responsible for freeing the value by calling XtFree.
- length
- Indicates the number of elements of data in value, where each
element has the size symbolized by format. If value is NULL,
length is 0.
- format
- Indicates whether the data in value should be viewed as a list of
char, short, or long quantities. Possible values are
8 (for a list of char), 16 (for a list of short), or 32 (for
a list of long).
XmTransferSetParameters(3), XmTransferSendRequest(3), and
XmTransferStartRequest(3).