ReadKey

   

Declaration:

Function ReadKey : Char;

Description:

The ReadKey function reads 1 key from the keyboard buffer, and returns this. If an extended or function key has been pressed, then the zero ASCII code is returned. You can then read the scan code of the key with a second ReadKey call.

Remark. Key mappings under Linux can cause the wrong key to be reported by ReadKey, so caution is needed when using ReadKey.

Errors:

None.

See also:

KeyPressed

Example

Program Example3;
uses Crt;

{ Program to demonstrate the ReadKey function. }

var
  ch : char;
begin
  writeln('Press Left/Right, Esc=Quit');
  repeat
    ch:=ReadKey;
    case ch of
     #0 : begin
            ch:=ReadKey; {Read ScanCode}
            case ch of
             #75 : WriteLn('Left');
             #77 : WriteLn('Right');
	    end;
	  end;
    #27 : WriteLn('ESC');	  
    end;
  until ch=#27 {Esc}           
end.