Assigning a new value to this attribute will cause any previously opened SinkFile to be closed. The first subsequent call to AST_WRITE will attempt to open the new file (an error will be reported if the file cannot be opened), and write data to it. All subsequent call to AST_WRITE will write data to the new file, until the SinkFile attribute is cleared or changed.
Clearing the attribute causes any open SinkFile to be closed. All subsequent data writes will use the sink function specified when the Channel was created, or will write to standard output if no sink function was specified.
If no value has been assigned to SinkFile, a null string will be returned if an attempt is made to get the attribute value.
AST A Library for Handling World Coordinate Systems in Astronomy