breset()
lclose()
Breset closes all files, also using doclose.
These functions implement the CLOSE and RESET statements.
For the aggrandizement of those so inclined, lclose closes the line printer (see filel(io)). Using doclose, this function effectively terminates the line printer process (if any), allowing for example a spooler to initiate physical printing or the line printer process to be reassigned in midstream. This function constitutes a blatant extension to the BASIC language and is, therefore, not directly supported by the syntax of the language. Nevertheless, the invocation of this function can be coded easily enough in a BASIC source program with the statement: “CALL LCLOSE.”
Files are closed automatically on exit or when the process receives any common signal. Attempting to close a file which is not open is not an error.
from The Basmark QuickBASIC Programmer’s Manual by Lawrence Leinweber