[Lazarus] read single char from STDIN

[Chris Kelling]

On Fri, Nov 18, 2011 at 11:48 AM, William Oliveira Ferreira wrote:

> i´ve always used
> c := ReadKey;
> ________________________________
> William de Oliveira Ferreira
> Bacharel em Sistemas de Informação

to expand on that, use the boolean function keypressed.  Remember on IBM 
compatibles that function keys send 2 scan codes.  The first, #0, to 
indicate a function key and not a normal key, and then the scan code for 
the actual keypress.  This includes the edit keys (insert, delete, home, 
end, pgup, pgdn, and arrow keys).

Here is a code fragment for an example:

if keypressed then
   begin
         c := readkey;
         if c = #0 then
             begin
                   c := readkey;
                   case c of
                          #132 : doSomething;
                             .
                             .
                             .
                   end; {case c}
             end {if #0 is true}
        else
           begin
             case c of
                    #132 : doSomethingElse;
                             .
                             .
                             .
             end; {case c}
           end; {if #0 is false}
   end; {if keypressed}

This is a Turbo Pascal convention (and FPC), not a standard or UCSD 
Pascal convention.  Remember that strings are not a standard type, 
either.
>
>
> 2011/11/18 Henry Vermaak <henry.vermaak at gmail.com>
>
>> On 18/11/11 16:18, Chris Kirkpatrick wrote:
>>
>>> It really needs get(c) but this function, together with put(c), 
>>> which
>>> were defined in Jensen & Wirth and all standard Pascals, has long 
>>> been
>>> missing from Turbo Pascal, and all its deriviatives such as 
>>> Freepascal.
>>>
>>
>> How does get(c) differ from read(c)?  The problem here is with the
>> terminal buffering the characters until return is pressed, hence the 
>> need
>> for re-configuring the terminal so that each key press is sent 
>> immediately.
>>
>> Henry
>>
>>
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>
>
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