SYNOPSIS
#include <Xm/Xm.h>
void XmTransferValue(
XtPointer transfer_id,
Atom target,
XtCallbackProc proc,
XtPointer client_data,
Time time);
DESCRIPTION
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).