To: "Dr. Ferenc Nagy" <[log in to unmask]>
From: [log in to unmask] (John Korb)
Subject: Re: Give me escape sequence detecting 132 column mode
 
>Dear John:
>
>Thank you for the detailed explanation. I would be glad if you can send
>me some sample program details.
>
>Some questions:
>
>Is CCTL an intrinsic?
>
>Next week I'll be here. In the period Aug 7-22 I'll be on vacations.
>May be, we can continue the discussion after that.
>
>                                           Thankx
>                                              Frank
 
Dear Frank:
 
The CCTL in the pseudo code is a reference to the CCTL (Carriage Control)
parameter of the FWRITE intrinsic.  When the decimal value 208 is supplied
as the Carriage Control parameter, FWRITE does not follow the write to the
terminal with a carriage return and line feed.  Instead, the cursor remains
located after the last character written to the terminal.  Carriage Control
208 is used when prompting for input, where the input is to be accepted on
the same line as the prompt.  Example.  FCOPY prompts with a ">" character.
If FCOPY were to FWRITE the ">" with CCTL 0, and the user were to input
"FROM=input;TO=output;NEW", the terminal display would look like:
 
   :fcopy
   <program heading>
 
   >
   FROM=input;TO=output;NEW
 
However, if FCOPY instead FWRITEs the ">" with CCTL 208, and the user inputs
"FROM=input;TO=output;NEW", the terminal display looks like:
 
   :fcopy
   <program heading>
 
   >FROM=input;TO=output;NEW
 
There is no carriage return, line feed after the ">" is written, and so the
prompt and input occur on the same line.
 
This is important in the code which determines the screen dimensions as if
the cursor sense escape sequence (ESC,a) is followed by a carriage return,
line feed, the cursor is no longer in the proper position to sense the
screen dimensions.  Thus, the FWRITE of the cursor sense escape sequence
(ESC,a) MUST performed with the CCTL parameter set to 208.
 
I hope this helps.  Be sure to let me know if you have additional questions.
 
John
--------------------------------------------------------------
John Korb                            email: [log in to unmask]
Innovative Software Solutions, Inc.
 
The thoughts, comments, and opinions expressed herein are mine
and do not reflect those of my employer(s), or anyone else.