Setting default screen modes for sub-programs
The OPTIONS RUN IN
instruction defines
the TTY mode to run sub-programs.
Syntax
OPTIONS RUN IN {FORM|LINE} MODE
Usage
When using character terminals,
the runtime system recognizes two screen display modes: line mode
(IN LINE MODE
) and formatted mode (IN FORM
MODE
). The OPTIONS
and RUN
statements
can explicitly specify a screen mode. The OPTIONS
statement
can set separate defaults for these statements.
After IN
LINE MODE
is specified, the terminal is in the same state
(in terms of stty options) as when the program began. This usually
means that the terminal input is in cooked mode, with interruption
enabled, and input not available until after a newline character
has been typed.
The IN FORM MODE
keywords
specify raw mode, in which each character of input becomes available
to the program as it is typed or read.
By default, a program
operates in line mode, but so many statements take it into formatted
mode (including OPTIONS
statements that set keys, DISPLAY
,
OPEN WINDOW
, DISPLAY FORM
, and
other screen interaction statements), that typical programs are
actually in formatted mode most of the time.
When the OPTIONS
statement
specifies RUN IN FORM MODE
, the program remains
in formatted mode if it currently is in formatted mode, but it does
not enter formatted mode if it is currently in line mode.
When the OPTIONS
statement specifies RUN
IN LINE MODE
, the program remains in line mode if it is
currently in line mode, and it switches to line mode if it is currently
in formatted mode.