Turbo Pascal ANSI Drivers
Version 1.12
Copyright (c) 1990 by Not So Serious Software
Original concept by Ian Silver
Design and implementation by Kevin Dean
Turbo Pascal is a registered trademark of Borland International Inc.
Coke is a registered trademark of Coca-Cola Ltd.
Introduction
"What you're getting."
----------------------------------------------------------------------
December 1989 (exam time)
Ian : "Kev, is there any way to get the Turbo Pascal CRT unit to
go to the modem?"
Kevin: "No. The CRT unit goes straight to the video hardware.
What are you trying to do?"
Ian : "I'm writing a game as a door for a BBS and I need video
control. What I really need is a good driver that will talk
nicely to a COM port - unlike DOS."
Kevin: "I wish you wouldn't keep doing this to me, Silver. You
always come up with interesting ideas for me to implement when I
don't have the time."
Ian : "Anyhow, we do need this, here ... have a Coke."
(Gratuitous bribery)
Kevin: "Silver, you don't _need_ it; you want it for writing a
game ... ok, maybe you _do_ need it."
- And thus a project was born.
---------------------------------------------------------------------
The routines in this package are intended to replace the Turbo
Pascal CRT unit (Turbo Pascal Version 5.0 or greater). The
procedures and functions provided in the ANSI unit mirror many of
the CRT unit functions but, instead of going directly to the
screen or through the BIOS, these functions go through a
user-defined text file device driver. For more information on
text file device drivers, please read Chapter 15, "Inside Turbo
Pascal", of the Turbo Pascal reference manual. No knowledge of
text file device drivers is needed to use the three ANSI
interface units (ANSICON, ANSICOM, and CONCOMIO) provided.
The ANSICON unit provides an ANSI interface to the MS-DOS
console and the MS-DOS device driver ANSI.SYS. One application
of this unit is in Turbo Pascal programs that would be portable
to generic MS-DOS environments, (e.g. environments that would be
incompatible with the CRT unit) while still maintaining full
control of the cursor and the video attributes.
The ANSICOM unit provides an ANSI interface to a modem or
serial device. One application (already in use as a door on a
bulletin board system) is in text video games that would be
played by remote over a phone line.
The CONCOMIO unit incorporates both the ANSICON and ANSICOM
units and gets input from the console, serial port, or both and
sends output to the console, serial port, or both. It does this
by chaining to the required input and output functions in the
other units.
Keep in mind that these drivers are mutually exclusive; you
cannot use more than one in any one program since each takes over
the standard input and output files and only one unit can have
control of those files. Only the last of these units in your
"uses" clause will actually have control.
Warranty
"Legalese - better safe than sorry."
Kevin Dean (hereafter referred to as "the author") makes no
warranty of any kind, expressed or implied, including, without
limitation, any warranties of merchantability and/or fitness for
a particular purpose. The author shall not be liable for any
damages, whether direct, indirect, special, or consequential
arising from a failure of this program to operate in the manner
desired by the user. The author shall not be liable for any
damage to data or property which may be caused directly or
indirectly by use of the program.
In no event will the author be liable to the user for any
damages, including any lost profits, lost savings, or other
incidental or consequential damages arising out of the use or
inability to use the program, or for any claim by any other
party.
Registration
"Capitalism at its finest."
A lot of late nights and Cokes went into the creation of these
routines. If you're going to use them regularly and would like
to show your appreciation (or at least help me in the upkeep of
my caffeine and sugar habit), please send a donation ($20
suggested) to:
Kevin Dean
Fairview Mall P.O. Box 55074
1800 Sheppard Avenue East
Willowdale, Ontario
CANADA M2J 5B9
CompuServe ID: 76336,3114
These drivers may come to you as part of the DoorLib package; if
you register DoorLib with its author, you will automatically be
registered for these drivers as well and no further payment will
be required.
Program Development
"How to write your very own ANSI programs."
Development of programs using these units may be done with the
units themselves or with the CRT unit. You may use any of the
standard CRT constants, procedures, functions, or variables with
the following exceptions:
Constants Procedures Functions Variables
--------- ---------- --------- -----------
BW40 DelLine all CRT CheckSnow
BW80 InsLine functions DirectVideo
Mono Sound are LastMode
CO40 NoSound available WindMin
CO80 TextMode WindMax
Font8x8 Window
C40
C80
If you develop your program using the CRT unit, just replace
the "uses CRT;" clause at the top of all your source files
with either "uses ANSI, ANSICON;", "uses ANSI, ANSICOM;", or
"uses ANSI, CONCOMIO;" depending on whether you want your output
to go through the standard DOS ANSI device driver, through a
serial port to a remote terminal, or both.
The ANSI I/O Driver
"The heart of the system."
----------------------------------------------------------------------
December 1989 (Christmas time, time for rest and relaxation)
Ian : "Ok, I've got the game finished, well... at least I think
it's finished. How's that ANSI driver coming along?"
----------------------------------------------------------------------
The ANSI I/O driver is a generic ANSI driver designed to
interface to any text file device driver. For more information
on text file device drivers, please read Chapter 15, "Inside
Turbo Pascal", of the Turbo Pascal reference manual.
The best tutorial you can get in writing your own ANSI unit
interface is by looking at the code for the three drivers
included with this package. The structure of the code is the
same in all cases, but for simplicity the best one to look at is
ANSICON.PAS.
The ANSI unit defines the following types:
type
IOFunc = function(var F : Text) : integer;
This is a function declaration of the text file device
driver interface to the Open, InOut, Flush, and Close
functions in Turbo Pascal.
type
IOFunctions =
record
NextOpen, NextInOut, NextFlush, NextClose : pointer
end;
This is a record of the linked I/O functions that are
called by the ANSI text file device drivers. These functions
actually handle the input from and output to the system. The
I/O functions in ANSI.PAS simply do the necessary character
interpretation necessary, e.g. update the cursor position
variables or change the screen color.
When a call is made to the AssignANSI procedure
(below), this record is passed as a parameter. This record is
stored in the UserData field of the file variable, and you
should not modify that field unless the modification merely
changes one of the pointers.
The field NextOpen should point to the Open function
written for your text file device. It is not necessary to
have an Open function defined for your device driver; if none
exists (NextOpen = nil) it will be ignored and the open
request (through a Reset or Rewrite) will proceed normally.
The field NextInOut should point to the InOut function
written for your text file device. If you do not assign a
value to the InOut function when you call AssignANSI,
(NextInOut = nil), you must be sure to assign a value to it
when the file is opened, i.e. when your Open function is
called. The Open function for ANSICON.PAS looks like this:
function ConsoleOpen(var F : Text) : integer;
begin
with TextRec(F) do
if Mode = fmInput then
IOFunctions(UserData).NextInOut := @ConsoleIn
else
IOFunctions(UserData).NextInOut := @ConsoleOut;
ConsoleOpen := 0
end;
Here the NextInOut pointer is assigned to a procedure to
handle either input or output depending on the mode in which
the file is opened. If no InOut function is defined, then any
calls to Read or ReadLn will return an I/O result of 161
(device read fault) and any calls to Write or WriteLn will
return an I/O result of 160 (device write fault).
The NextFlush function flushes the input or output
buffer if necessary. It is called at the end of every read or
write and so you are strongly advised to define it; if you do
not, you will have to wait until the output buffer (128
characters) is full before it is written to the screen. At
the very least it should chain to the output function defined
for the current file. The following is the Flush function
from ANSICON.PAS:
function ConsoleFlush(var F : Text) : integer;
begin
with TextRec(F) do
if Mode = fmInput then
{ Ignore flush request }
ConsoleFlush := 0
else
{ Chain to F's default output routine }
ConsoleFlush := IOFunc(InOutFunc)(F)
end;
I advise against calling your own output function directly
from the flush function because by doing so you may bypass the
ANSI output function. This will prevent the internal cursor
position from being updated and may affect your colors as
well.
The NextClose function is called when a text file is
closed. It is not necessary to define this function unless
you have to do some cleanup before closing the file.
Please remember that these functions in the I/O chain
are treated just like any other text file device driver; if
the return code is non-zero, then Turbo Pascal will signal an
I/O error which you must check to ensure success.
The ANSI unit defines the following character constants:
const
NUL = #0; { The NUL character }
BRK = #3; { Ctrl-C }
BEL = #7; { Bell }
BS = #8; { BackSpace }
TAB = #9; { Tab }
LF = #10; { Line feed }
FF = #12; { Form feed }
CR = #13; { Carriage return }
EOF_ = #26; { End-of-file marker }
ESC = #27; { Escape }
---------------------------------------------------------------------
January 1990
Ian : "Kev, the colors are all messed up. I do wish you'd get a
color monitor."
Kevin: "Ok, I'll look into it."
Ian : "I looked at your code, the bug is right in this routine."
Kevin: "No, there's no problem there. I'm checking something
else here ..."
Ian : "I tell you, the bug is right here!"
Kevin: "No, that's not it. Give me a few minutes ..."
Ian : "If you say so."
(half an hour later)
Kevin: "You're right. That code you were looking at _was_ the
problem."
Ian : <grin>
--------------------------------------------------------------------
The ANSI unit defines the following video constants:
const
Black = 0;
Blue = 1;
Green = 2;
Cyan = 3;
Red = 4;
Magenta = 5;
Brown = 6;
LightGray = 7;
DarkGray = 8;
LightBlue = 9;
LightGreen = 10;
LightCyan = 11;
LightRed = 12;
LightMagenta = 13;
Yellow = 14;
White = 15;
Blink = 128;
The ANSI unit defines the following constants:
const
On = true;
Off = false;
These are passed to the ANSIStatus procedure to turn
the ANSI control sequences on or off (default is On).
The ANSI unit defines the following variables:
var
WrapAround : boolean;
True if the cursor wraps around from one line to the
next when it reaches the end of a line. Default value is
true.
var
MaxX, MaxY : byte;
These hold the screen dimensions. MaxX is the maximum
number of columns (default 80) and MaxY is the maximum number
of rows (default 25). Values of 0 mean no maximum. These
variables are used in part to determine the current cursor
position.
var
TabLength : byte;
This is the distance between tab stops. Default value
is 8.
var
TextAttr : byte;
This defines the current screen color. It is
compatible with the TextAttr variable in the CRT unit.
Default value is LightGray.
var
ANSIFile : Text;
This is the file to which all ANSI control sequences
are written. It must be explicitly assigned to a device or
file and opened before your program is run. Once you have
assigned and opened this file it is advised that you make an
explicit call to either GotoXY or ClrScr to fix the cursor in
a known position. The internal mechanisms have no way of
knowing what the initial position is.
var
CheckEOF : boolean;
This variable is used by text file device drivers
linked to the ANSI output routines. If true, the driver
should check for the end-of-file marker (Ctrl-Z) when reading
from its device and signal end of file if found. Default
value is false.
var
CheckBreak : boolean;
This variable is used by text file device drivers
linked to the ANSI output routines. If true, the driver
should check for Ctrl-Break or Ctrl-C when reading from its
device and signal a break if found. Default value is true.
The ANSI unit defines the following procedures and functions:
function Redirected : boolean;
This function returns true if either the standard
input or standard output has been redirected. This may be
useful in conjunction with the ANSICON or CONCOMIO units if
you want to guarantee that input will come from the keyboard
and output will go to the screen.
procedure ANSIStatus(Status : boolean);
Status is either On or Off (defined above). If On,
ANSI control sequences are used as normal. If Off, all ANSI
control sequences are ignored; the output is in teletype mode.
Default mode is On.
procedure AssignANSI(var F : Text; IOChain : IOFunctions);
This assigns the file F to the ANSI text file device.
The parameter IOChain must contain a record of valid I/O chain
functions as described above.
procedure ClrEol;
Sends the ANSI control sequence to clear to the end of
the current line.
procedure ClrScr;
Sends the ANSI control sequence to clear the screen.
procedure Delay(MS : word);
Delays program execution for MS milliseconds.
procedure GotoXY(X, Y : byte);
Sends the ANSI control sequence to position the cursor
at (X, Y). If X is not in the range 1 .. MaxX or Y is not in
the range 1 .. MaxY then this request is ignored. If MaxX and
MaxY are both 0, no check is made and the procedure positions
the cursor blindly.
function WhereX : byte;
Returns the current X position of the cursor. Since
the internal mechanisms have no way of knowing what the
initial cursor position is, this function is unreliable unless
you make an explicit call to either GotoXY or ClrScr to fix the
cursor in a known position.
function WhereY : byte;
Returns the current Y position of the cursor. Since
the internal mechanisms have no way of knowing what the
initial cursor position is, this function is unreliable unless
you make an explicit call to either GotoXY or ClrScr to fix the
cursor in a known position.
procedure HighVideo;
Turns on high video by setting the high video bit of
TextAttr.
procedure LowVideo;
Turns on low video by resetting the high video bit of
TextAttr.
procedure NormVideo;
Resets TextAttr to the original color at startup
(LightGray).
procedure TextBackground(Color : byte);
Changes the text background to Color.
procedure TextColor(Color : byte);
Changes the text foreground to Color; the text
background is not affected.
Where any of the above constants, variables, procedures, or
functions have the same name as in the CRT unit, the
functionality is the same.
This is a bare minimum replacement for the CRT unit. Certain
variables, procedures, and functions cannot be handled by the
ANSI unit because they are too tightly bound to the particular
device. Two such functions, for example, are KeyPressed and
ReadKey; these cannot be unbound from the device and so the ANSI
unit does not implement them. It is up to you to create these
missing variables, procedures, and functions if you need them.
The ANSICON, ANSICOM, and CONCOMIO units provided implement some
of these missing functions. They are described in the following
sections.
The ANSICON Console Driver
"How to make your keyboard and screen look like any other terminal."
The ANSICON console driver takes all input from the standard
input device (the console) and sends all output to the standard
output device (the console) via the ANSI.SYS device driver. To
uses this unit, make sure you have the statement
"DEVICE=ANSI.SYS" in your CONFIG.SYS file; for more information
on the CONFIG.SYS file, please see your DOS manual.
This unit can be used with the ANSI unit as a replacement for
the Turbo Pascal CRT unit. Programs developed using these units
may be ported to generic MS-DOS environments where the CRT unit
may not be compatible.
When you include the ANSICON unit in your program, it
automatically assigns the standard input and output files and the
ANSI file to the ANSICON I/O functions.
The ANSICON unit defines the following procedures and functions:
procedure AssignCON(var F : Text);
This assigns the file F to the console by defining its
I/O chain functions and then assigning the file to the ANSI
device above.
function KeyPressed : boolean;
Returns true if a key is waiting in the keyboard
buffer.
function ReadKey : char;
Reads the next key from the keyboard buffer.
Where any of the above constants, variables, procedures, or
functions have the same name as in the CRT unit, the
functionality is the same.
The ANSICOM Communications Driver
"How to make any other terminal look like your keyboard and screen."
----------------------------------------------------------------------
January 1990 (back to university, second term)
Ian : "Four assignments eh? That's a tough break ... so how's
that code coming along?"
Kevin: "SILVER!!!"
----------------------------------------------------------------------
The ANSICOM communications driver takes all input from and
sends all output to a single modem or serial device. The driver
is interrupt-driven, which means that data can be received and
transmitted while the computer is engaged doing something else.
The advantage of this unit is that it treats your modem almost
exactly the same way as the Turbo Pascal CRT unit treats your
keyboard and screen.
When developing programs that will use the ANSICOM unit, it is
best to design them using either the Turbo Pascal CRT unit or the
ANSICON unit provided with this package. In this way, you can
fully design, test, and debug your program on your own machine
before committing it to the serial port.
When you include the ANSICOM unit in your program, it
automatically assigns the standard input and output files and the
ANSI file to the ANSICOM I/O functions.
-------------------------------------------------------------------
Kevin: "I finally figured out why the error handler was not
working properly. Not only had I failed to declare it as a far
procedure, but it was going through infinite recursion: the halt
procedure in the error handler called the flush procedure to
flush the output file, which in turn called the error handler
(because the error had not been cleared), which in turn called
halt ... system go whiirrrrrrrrrrrrr ..."
Ian : "Oh lovely. We should work for the government ...
perpetual job creation."
--------------------------------------------------------------------
The ANSICOM unit defines the following types:
type
ErrorProc = procedure(var Error : word);
This is the communications error handling procedure.
Your error handling procedure must be of the above type and
must be declared as a far procedure (use the {$F+} compiler
directive). The parameter error will have one or more of the
following flags set: ReceiveOverrun, TransmitOverrun,
ParityError, FramingError, BreakDetect, CommTimeOut,
NoCarrier, or CtrlBreak. These are described below. If your
error procedure is to return control to the communications
routines, you may want to clear some or all of the error
flags so that you don't have to handle that error the next
time the procedure is called. To clear all error flags set
Error equal to NoCommError (0).
To test for a communications error, mask the Error
parameter with one or more of the above flags. For example,
{ Halt if lost carrier }
if Error and NoCarrier <> 0 then
begin
ReleaseCOM;
halt(1)
end;
{ Ignore parity and framing errors }
if Error and (ParityError or FramingError) <> 0 then
Error := Error and not (ParityError or FramingError);
If you want to send an error message to the console
(not the serial port), you will have to open the console as a
file since the ANSICOM driver redirects the standard output
file to the modem. Thus:
Assign(ConF, 'CON');
Rewrite(ConF);
if Error and NoCarrier <> 0 then
begin
WriteLn(ConF, 'Error : No carrier');
ReleaseCOM;
halt(1)
end;
The ANSICOM unit defines the following constants:
const
Init = true;
NoInit = false;
These constants are used when installing the
communications routines. If the modem is to be initialized,
i.e. its baud rate and data format has yet to be set up, then
use Init in the call to InitCOM. If the modem is already
initialized or on-line, use NoInit in the call to InitCOM to
prevent the modem from losing the connection.
const
SyncTransmit = true;
AsyncTransmit = false;
These constants are used when installing the
communications routines. Synchronous transmission means that
the program output (through Write or WriteLn) waits until all
characters have been transmitted before returning control to
the program. This approach is advised when writing
interactive programs such as video games; use the SyncTransmit
constant when initializing the modem. If you don't want to
wait for the output to be transmitted, use AsyncTransmit and
control will be returned to your program while the ANSICOM
unit takes care of the transmission in the background.
const
NoCommError = $0000;
No communications error.
const
ReceiveOverrun = $0001;
Either a character arrived over the modem before the
ANSICOM unit had a chance to remove the previous character or
the receive buffer is full (your program is not reading the
data as it comes across the line).
const
TransmitOverrun = $0002;
The transmission buffer is full. This error occurs
only in asynchronous transmission when you write more to the
modem than it can handle in that length of time.
const
ParityError = $0004;
FramingError = $0008;
Data arriving over the modem has somehow been
corrupted. The character or characters affected were lost in
transmission.
const
BreakDetect = $0010;
The remote modem is requesting that you break the
connection. Suggested action is to disconnect the modem with
a call to the Disconnect procedure.
const
CommTimeOut = $0020;
The modem timed-out (the remote modem has probably
gone off-line).
const
NoCarrier = $0040;
The modem has lost the carrier signal.
const
CtrlBreak = $0080;
A Ctrl-C character has been received and CheckBreak
(above) is true.
const
NotOnline = $0100;
You are trying to read from the communications port
without having initialized the communications routines.
The ANSICOM unit defines the following functions and procedures:
function InitCOM(COMPort : byte; Baud : integer; Bits : byte;
Parity : char; Stop : byte; Init : boolean; Sync : boolean;
Error : pointer) : integer;
This initializes the modem, installs the
communications interrupt, sets the desired transmission
synchronization, and installs a user-defined error handler.
The parameters are:
COMPort - Port number from 1 to 4
Baud - Desired baud rate
Bits - Number of data bits (5 to 8)
Parity - Parity type ('E'ven, 'O'dd, 'M'ark,
'S'pace, or 'N'one)
Stop - Number of stop bits (1 or 2; to get
1.5 stop bits for 5 data bits, use
2 stop bits)
Init - Use the constants Init to initialize
the modem with the given data format
or NoInit if the modem has already
been initialized.
Sync - Use the constants SyncTransmit for
synchronous transmission or
AsyncTransmit for asynchronous
transmission (described above)
Error - Pointer to a user-defined error
handler of the type ErrorProc
(defined above) or nil if no error
handler is desired
This function returns 0 if successful or 1 if not
(invalid COM port number or data format).
function SetBaud(Baud : integer; Bits : byte; Parity : char;
Stop : byte) : integer;
This function is useful if you want to change the data
format on the fly, for example if the modem, previously
initialized at 2400 baud, connects at 1200. To use this
function, you must first have initialized it using the InitCOM
function.
The parameters are:
Baud - Desired baud rate
Bits - Number of data bits (5 to 8)
Parity - Parity type ('E'ven, 'O'dd, 'M'ark,
'S'pace, or 'N'one)
Stop - Number of stop bits (1 or 2; to get
1.5 stop bits for 5 data bits, use
2 stop bits)
This function returns 0 if successful or 1 if not
(modem not previously initialized or invalid data format).
procedure Disconnect;
Disconnects the modem by turning off the carrier.
procedure ReleaseCOM;
Releases the modem by resetting the modem state to its
initial configuration. If the modem was initialized (by
specifying Init in InitCOM) then it is disconnected.
procedure AssignCOM(var F : Text);
This assigns the file F to the modem by defining its
I/O chain functions and then assigning the file to the ANSI
device above.
function KeyPressed : boolean;
Returns true if a key is waiting in the modem input
buffer.
function ReadKey : char;
Reads the next key from the modem input buffer.
Where any of the above constants, variables, procedures, or
functions have the same name as in the CRT unit, the
functionality is the same.
The CONCOMIO Console and Communications Driver
"How to make your keyboard and screen look like any
other terminal and vice versa."
------------------------------------------------------------------
February 1990
Kevin: "There. Done. Documented. It's all yours."
Ian : "Great! Now, is there any way to get the output to go to
both the console and the modem and to get input from both as
well?"
Kevin: "(sigh) Alright ... give me another hour ... (grumble,
grumble)"
------------------------------------------------------------------
The CONCOMIO driver takes its input from the console, the
communications port, or both, depending on how CONCOMIO has been
configured. To use this unit, you must have ANSI.SYS installed
in your CONFIG.SYS file (see ANSICON documentation above).
When you include the CONCOMIO unit in your program, it
automatically assigns the standard input and output files and the
ANSI file to the CONCOMIO I/O functions.
All types, constants, variables, procedures, and functions
defined in ANSICOM are also defined in CONCOMIO (with the
exception of AssignCOM). As before, you must initialize the
modem, install an error handler, etc. In addition to the stuff
declared in ANSICOM, CONCOMIO has its own declarations described
below.
The CONCOMIO uses both the ANSICON and ANSICOM units to handle
the input and output. The sole purpose of this unit is to direct
the input and output calls to the correct handlers.
Communications error handlers for the CONCOMIO unit function
exactly the same way as they do for the ANSICOM unit.
However, since the console is part of the CONCOMIO routines, you
do not need to open the console as a separate file; instead, set
the variable ActiveOutput := ConsoleActive. The variable
ActiveOutput and constant ConsoleActive are described below.
The CONCOMIO unit defines the following constants:
const
NoneActive = $0000;
No text file device driver is active for this
operation (input or output, see below).
const
ConsoleActive = $0001;
The console device driver is active for this operation
(input or output, see below).
const
CommActive = $0002;
The communications device driver is active for this
operation (input or output, see below).
const
BothActive = ConsoleActive or CommActive;
Both the console and communications device drivers are
active for this operation (input or output, see below).
The CONCOMIO unit defines the following variables:
var
ActiveInput : word;
This is the active input device. Valid values are
NoneActive (no input allowed), ConsoleActive (input from
console only allowed), CommActive (input from modem only
allowed), and BothActive (input from both console and modem
allowed).
If the value is NoneActive, any Read or ReadLn
operation will return an I/O result of 161 (device read
fault).
var
ActiveOutput : word;
This is the active output device. Valid values are
NoneActive (no output allowed), ConsoleActive (output to
console only allowed), CommActive (output to modem only
allowed), and BothActive (output to both console and modem
allowed).
If the value is NoneActive, any Write or WriteLn
operation will return an I/O result of 160 (device write
fault).
The CONCOMIO unit defines the following procedures and functions:
procedure AssignCONCOM(var F : Text);
This assigns the file F to the console and the modem
by defining its I/O chain functions and then assigning the
file to the ANSI device above.
function KeyPressed : boolean;
Returns true if a key is waiting in the keyboard or
modem buffer, depending on the value of ActiveInput.
function ReadKey : char;
Reads the next key from the keyboard or modem buffer,
depending on the value of ActiveInput.
Where any of the above constants, variables, procedures, or
functions have the same name as in the CRT unit, the
functionality is the same.
When using the CONCOMIO unit, you must be sure to initialize
the modem using the InitCOM() call since CONCOMIO does in fact
use the modem.
WARNING: By default, the CONCOMIO startup routine sets
CheckBreak to false. This is because a Ctrl-Break in the ANSICON
driver generates INT 23h, the Ctrl-Break interrupt, and does not
allow the communications routines to do any cleanup. When this
happens, the communications interrupt in the ANSICOM driver may
not be properly released and your computer may be left in an
unknown state.
Demonstration Programs
"Cut-and-paste code."
The files DEMOCON.EXE (source DEMOCON.PAS), DEMOCOM.EXE
(source DEMOCOM.PAS), and DEMOBOTH.EXE (source DEMOBOTH.PAS)
demonstrate simple applications of the ANSICON or ANSICOM units
or both respectively. These programs handle line-oriented input
and output and some simple color and screen control.
To run DEMOCON, just type DEMOCON at the DOS prompt. After
you enter your name, a box showing your name, current colors, and
the cursor position will be displayed. The colors will change
randomly.
To run DEMOCOM, your modem must be on-line to a remote
terminal. The baud rate at which it is connected is really
immaterial since your modem will not be initialized by the
DEMOCOM program itself. However, you must be connected at 8 data
bits. The remote terminal will see exactly the same thing that
you saw in the DEMOCON program.
To run DEMOBOTH, your modem must be on-line to a remote
terminal. The baud rate at which it is connected is really
immaterial since your modem will not be initialized by the
DEMOBOTH program itself. However, you must be connected at 8
data bits. In this case, both the remote terminal and your
screen will display the same thing and each will have the ability
to enter data.
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