Retrieve a file descriptor to write the content of the clipboard selection to.
The content should be formatted according to the mime type of the mime type passed via the [signal@Session:
XdpSession:selection-transfer] that carried the passed serial number.
| this |
a [class@Session] |
| serial |
a serial number |
|
a file descriptor to a pipe to write the clipboard selection content to, or -1 on error. The caller must close the file descriptor when finished with it. |