The BLANK clause clears a line of a screen or the whole screen before a screen item is displayed.
- In addition to Compiler directives which provide flagging and modify the reserved word list, the following directive may impact
either the syntax or semantics described in this section.
- OLDBLANKLINE - specifies that the BLANK LINE clause has the same effect as ERASE EOL; that is, all characters to the right
of the cursor are deleted.
- The BLANK SCREEN clause can be specified in any screen description entry.
- The BLANK LINE clause can be specified only for elementary items.
- The BLANK SCREEN clause is executed before DISPLAY of a screen data item, no matter where it appears. If the clause is specified,
all the screen is cleared and the cursor is placed at line 1, column 1.
- When BLANK LINE is specified, blanking begins at column 1 of the line specified for the screen data element in whose description
it is included and continues through the end of the line. The cursor remains in the same position as before the BLANK LINE
- If neither the BLANK nor the ERASE clause is specified, only the particular character positions corresponding to the screen
data element are modified when the element is displayed. The rest of the screen content remains the same.
- The BLANK SCREEN clause causes the screen to return to its default foreground and background colors. For additional effects,
if the screen item is subject to a FOREGROUND-COLOR or BACKGROUND-COLOR clause, see the topics on those clauses.
- The BLANK clause is ignored in an ACCEPT statement.
- When the BLANK SCREEN clause is used, only color options (foreground-color and background-color) should be used on the same
screen. Other attributes are accepted but ignored.