Practical Programming in Tcl & Tk, Third Edition

Selection Handlers

The selection handle command registers a Tcl command to handle selection requests. The command is called to return the value of the selection to a requesting application. If the selection value is large, the command might be called several times to return the selection in pieces. The command gets two parameters that indicate the offset within the selection to start returning data, and the maximum number of bytes to return. If the command returns fewer than that many bytes, the selection request is assumed to be completed. Otherwise, the command is called again to get the rest of the data, and the offset parameter is adjusted accordingly.

You can also get a callback when you lose ownership of the selection. At that time it is ...