R-OPEN-FUNCTION (op-code 1)

This routine opens an existing relative file. If it is successful, the value in RETURN-CODE should be moved to a data item that is USAGE HANDLE. This data item is passed as the open file handle to the other file handling routines. If it fails, RETURN-CODE is set to a NULL value.

The R-OPEN-FUNCTION routine takes four required parameters, and one optional parameter: filename, mode, maxsize, minsize, and blocks.