Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!csun!Twg-S5!abcscnuk
From: abcscnuk@Twg-S5.uucp (Naoto Kimura (ACM))
Newsgroups: comp.lang.pascal
Subject: Re: Disable Control-Break in TP version 4
Message-ID: <1990Oct12.111159.23213@csun.edu>
Date: 12 Oct 90 11:11:59 GMT
References: <4387@peora.ccur.com> <1990Oct11.120204.2912@uwasa.fi>
Sender: news@csun.edu (News Administrator)
Organization: csun
Lines: 91

In article <1990Oct11.120204.2912@uwasa.fi> ts@uwasa.fi (Timo Salmi) writes:
]... ( stuff deleted ) ...
]
] A: This very frequently asked question is basically a case of RTFM
](read the f*ing manual). But this feature is, admittedly, not very
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
]prominently displayed in the Turbo Pascal reference.
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Quite true!  It took me quite a while trying to remember where I saw it
(in the description of the Crt unit), so I could mention the page number
on which it appeared.  I found it a few days ago, but I can't say what
page number since I don't have the manual with me.

]   There is a CheckBreak variable in the Crt unit, which is true by
]default. To turn if off use
]     uses Crt;
]     :
]     CheckBreak := false;
]     :

One interesting point about the CheckBreak variable is that it is the
same as the *undocumented* CBREAK variable in version 3.0 (I remember
finding it one day when snooping around in the executable with a binary
file editor and never knew what it was for until I read the manual for
version 4.0).  This fact is mentioned in the appendix discussing the
differences between version 3.0 and version 4.0/5.0.

]Besides turning off break checking this enables you to capture the
]pressing of the break key as you would capture pressing ctrl-c. In
]other words you can use e.g.

Minor correction is needed in the code:

]     :
]procedure TEST;
]var key : char;
]begin
]  repeat
]    if KeyPressed then
]      begin
]        key := ReadKey;
]        case key of
	   (* account for special keys (F1..F10, arrows, etc.) *)
	   (* otherwise we can misinterpret them               *)
           #0 : begin
		    write(' (0,',ord(ReadKey),') ');
		    Key := ReadKey;
		end;
]          #3 : begin writeln ('Break'); exit; end;  {ctrl-c or break}
]          else write (ord(key), ' ');
]        end; {case}
]      end; {if}
]  until false;
]end;  (* test *)
]     :

The above code would change slightly for version 3.0:

]procedure TEST;
]var key : char;
]begin
]  repeat
]    if KeyPressed then
]      begin
]        key := ReadKey;
]        case key of
           (* account for special keys (F1..F10, arrows, etc.) *)
           (* otherwise we can misinterpret them               *)
           #27 :if not KeyPressed then
                    write('27 ')
                else begin
                    write(' (0,',ord(ReadKey),') ');
                    Key := ReadKey;
                end;
]          #3 : begin writeln ('Break'); exit; end;  {ctrl-c or break}
]          else write (ord(key), ' ');
]        end; {case}
]      end; {if}
]  until false;
]end;  (* test *)

]... ( stuff deleted ) ...
]...................................................................
]Prof. Timo Salmi        (Moderating at anon. ftp site 128.214.12.3)

                //-n-\\			 Naoto Kimura
        _____---=======---_____		 (abcscnuk@csuna.csun.edu)
    ====____\   /.. ..\   /____====
  //         ---\__O__/---         \\	Enterprise... Surrender or we'll
  \_\                             /_/	send back your *&^$% tribbles !!