Writes the required number of blank spaces to ensure that the next character will be written in a given column.
The generic function stream-advance-to-column writes enough blank spaces to stream to ensure that the next character is written at column . The generic function returns t if the operation is successful, or nil if it is not supported for this stream.
This function is intended for use by print and format ~t . The default method uses stream-line-column and repeated calls to stream-write-char with a #\Space character, and returns nil if stream-line-char returns nil .