Terminals

A terminal is a serial non-store device. The TTerminal class descends from the TDevice class.

type TDevice = class

public

procedure Cancel_Input ;

procedure Cancel_Output ;

function Pending_Input : boolean ;

function Pending_Output : boolean ;

procedure Poll ;

end ;

type TTerminal = class( TDevice )

public

procedure Output( S : PChar ) ;

function Input( var C : integer ) : boolean ;

procedure Clear_Typeahead ;

function Peek : char ;

function Video : boolean ;

function Get_OnNewChar : TCharNotify ;

procedure Set_OnNewChar( Value : TCharNotify ) ;

end ;

The following table describes the TDevice methods:

Method	Description
Cancel_Input	Cancels pending input or input operation.
Cancel_Output	Cancels pending output or output operation.
Pending_Input	Returns True if there is any pending input or input operation.
Pending_Output	Returns True if there is any pending output or output operation.
Poll	Polls the device for operation completion.

The following table describes the TTerminal methods:

Method	Description
Output	Transmits the passed data. The data ends with a null.
Input	Retrieves the next waiting character from the device buffer.
Clear_Typeahead	Clears any characters waiting in the device buffer.
Peek	Retrieves the next waiting character from the device buffer but doesn't remove it.
Video	Returns true if the terminal is capable of video operations. Otherwise it returns false.
Get_OnNewChar	Returns the pointer to the new character delegation.
Set_OnNewChar	Sets the new character delegation.