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README File
Release Notes for Microsoft(R) QuickPascal
(C) Copyright Microsoft Corporation, 1989
This on-line file contains information about Microsoft(R) QuickPascal
for MS-DOS(R). The information in this on-line file is more up to
date than that in the manuals.
Microsoft improves its language documentation at the time of
reprinting, so some of the information in this on-line file may
already be included in your manuals. Where the information in this
file conflicts with the manuals, assume that this file contains the
correct information.
============================< Contents >=============================
This file has two parts.
Part Topic
---- -----
1 Additional Functionality and QuickPascal Description
2 Recommendations and Limits
===< Part 1: Additional Functionality and QuickPascal Description >==
Additional Graphics Function
----------------------------
QuickPascal contains a new MSGraph function, _GrStatus, which returns
the status of the most recently executed graphics routine. _GrStatus
lets your programs check for errors that can occur when executing
graphics routines.
_GrStatus is not covered in "Pascal by Example," but it is completely
documented in the on-line help system. See the on-line program
PALETTE1 for an example of how to use _GrStatus.
Additional Graphics Procedure
-----------------------------
The graphics unit, MSGraph, includes two procedures that draw
polygons. The procedures have the form:
PROCEDURE _Polygon( control : Integer; VAR pointarray;
numpoints : Integer );
PROCEDURE _Polygon_wxy( control : Integer; VAR pointarray;
numpoints : Integer );
They both draw a polygon in the current color. They either draw
just the outline of the shape or fill the entire shape depending
on the value of control, either _GBorder or _GFillInterior.
The variable pointarray is an array of _XYCoords (or _WXYCoords
for _Polygon_wxy), each of which specifies one of polygon's
verticies. The argument numpoints indicates the number of elements
in pointarray (the number of verticies).
_SetWriteMode, _SetLineStyle, and _SetFillMask all effect the
output from _Polygon and _Polygon_wxy.
Possible return values by _GrStatus for _Polygon and _Polygon_wxy
are: _GrNotInProperMode, _GrInvalidParameter, _GrInsufficientMemory,
_GrNoOutput, and _GrClipped.
For related procedures see _LineTo, _Rectangle, _FloodFill,
_SetColor, _SetWriteMode, _SetLineStyle, and _SetFillMask.
Additional Graphics Routines for Appendix D
-------------------------------------------
The following routines appear in the on-line help, but were omitted
from Appendix D, under MSGraph, in "Pascal by Example":
PROCEDURE _GetGTextVector( VAR x, y : Integer );
Returns the orientation of text as set by _SetGTextVector and used by
_OutGText. _GetGTextVector appears in Appendix D, but uses the wrong
parameters.
FUNCTION _GrStatus : Integer;
Returns the status of the most recently called graphics routine.
FUNCTION _GetWriteMode : Integer;
Returns the current operand applied to line drawing: _GOR, _GAND,
_GPRESET, _GPSET, or _GXOR.
PROCEDURE _Polygon( control : Integer; VAR pointarray;
numpoints : Integer);
Draws a polygon at the current cursor location. See the general
description in the previous README entry under "Additional Graphics
Functions."
PROCEDURE _Polygon_wxy( control : Integer; VAR pointarray;
numpoints : Integer);
Draws a polygon at the current cursor location. See the general
description in the previous README entry under "Additional Graphics
Functions."
Additional Compiler Directives
------------------------------
The $E, $G, and $O compiler directives have been added to
QuickPascal. $N+ and $N- are also discussed here to add more
information to the general description of compiler directives that
is given in Appendix B of "Pascal by Example."
The plus (+) and minus (-) turn the instructions on or off,
respectively. (Remember you can also set any functional compiler
directive from within the QuickPascal environment.)
$E+/- Included for Turbo Pascal compatibility.
$G+/- Generates instructions for the 286 processor. This directive
lets your programs take advantage of the additional speed
provided by 80286 processors. Default is $G- (no 286
instructions). Programs compiled with $G+ will run only on
computers that use the 286, 386, or 486 processors.
$N+ Generates instructions for the 8087 family of math
coprocessors. All floating types are supported with their full
range and precision (19-20 digits). Programs compiled with $N+
require a math coprocessor to run.
$N- Invokes the alternate math package, which does not require a
math coprocessor. Note that this is not an emulator.
Alt math supports all long floating-point types, but Extended
and Comp types do not have the range or precision available
with a coprocessor. With $N-, Extended data have the same range
and precision as Double types. The Comp type has the same range
as with $N+ but precision is limited to 15-16 digits.
(See the on-line help for more information about type ranges
and precision.) $N- is the default (no coprocessor required).
$O+/- Ignored. Included for Turbo Pascal compatibility.
QP.EXE Command-Line Arguments
-----------------------------
The QuickPascal integrated environment does not use many command-line
arguments. Mostly, parameters are set within the environment. For
this reason, the only command-line arguments that are needed are
those that enable the environment to start properly.
Choose one of the following options to specify the color palette for
QuickPascal to use in its interface:
/1
/2
/3
/B For monochrome or LCD
/S Save Color Palette - VGA only (default not saved)
Use the /S option to save the color palettes on the VGA. By default
this switch is not active. /S must be used if you have a VGA and your
graphics program is manipulating the VGA color palettes. This switch
causes the color palettes to be saved to disk or memory. QP swaps the
palettes back when returning to the QP environment from your program.
Choose one of the following options to specify how many display rows
to use:
/25
/43
/50
Depending on your computer's memory configuration, you can choose how
QuickPascal works with a temporary file that it creates, called a
'swap file'. (/SWAP options tell QuickPascal how to handle the swap
file.):
/SWAP:{ON[=file]|OFF|EMS|DISK[=file]}
OFF Turns off all swapping. The default option is OFF.
ON Swaps to Expanded Memory Specification (EMS) if present or to
disk (if there is no EMS). This requires 1024K bytes of hard
disk space.
EMS Swaps to EMS.
DISK Swaps to disk. This option is particularly useful when
developing very large or memory-intensive applications.
The ON and DISK options let you specify a name for the swap file
with the '=file' option. QuickPascal will remember this name until
you explicitly remove it (by specifying '=' with no file name). The
default file name is QP###### (no extension). The # are randomly
generated. QuickPascal decides where to place the swap file
by looking for a TEMP (or TMP if you do not use TEMP) environment
variable, and placing the swap file in that directory. If you do not
provide a TEMP or TMP directory, QuickPascal will put the swap file
in the current directory.
QuickPascal saves the /SWAP options in the QP.INI file, so you only
need to specify the option once. Thereafter, QuickPascal always
starts with that option. To change the option, specify a different
/SWAP option when you start QuickPascal.
If QuickPascal crashes for any reason, delete the swap file (if
you do not keep temporary files in a RAM disk). If you plan to swap
to your disk or to EMS, you need a minimum of one megabyte of free
space. Run the CHKDSK (check disk) command if you are unsure
of the amount of available space on your system.
In addition to the display parameters, you may include one or more
(up to nine) source file names on the command line:
qp [ filename [ ... filename ]]
QuickPascal attempts to open a window for each listed file. It
detects listed files that do not exist and asks whether they should
be created.
QPL.COM Command-Line Arguments
------------------------------
The command-line version of the compiler makes extensive use of
command-line parameters to control the compilation process:
/DIdentifier[;...;Identifier]
This option lets you define symbols that can be tested in the source
code with {$IFDEF} or {$IFNDEF}.
The following options specify the directories to use when searching
for or creating files.
Option Syntax Files
------------------------- -----
/E Directory .EXE
/P Directory [;Directory] .PAS
/I Directory [;Directory] .INC
/O Directory [;Directory] .OBJ
/U Directory [;Directory] .QPU
/B
This option tells the compiler to build the specified file(s). If
/B is not given, QuickPascal simply compiles the file(s).
The /B compiler option directs QuickPascal to check all of the
dependencies of the file being compiled. If any of the source
files have been modified since they were last compiled, they
are compiled now. This ensures that the new .EXE file always
reflects the contents of the most recent source code.
/R
This command-line switch forces a compile of all the units and files
upon which the file being compiled is dependent. Compilation occurs
whether or not the unit or file has changed.
/$ {x[+|-]|M[sss],[nnn],[xxx]} [,x([+|-] | M[sss],[nnn],[xxx])]...
Use the /$ option to enable or disable QuickPascal directives. The
syntax of this command is identical to the syntax used within a
source program. For example, to turn off range-checking in a source
program, either insert a {$R-} directive directly into a program:
{$R-}
PROGRAM source;
BEGIN
...
END.
or specify /$R- on the command line:
QPL /$R- source.pas
The /$ option may be used to set any compile-time directive:
A Align data
B Boolean complete evaluation
D Debug information
F Force far calls
G Generate instructions for 80286
I I/O checking
M Method calls checking
M Set memory parameters
N Numeric processing
R Range checking
S Stack checking
V VAR string checking
Note that the M directive has two uses. When followed by + or -, it
turns method-call checking on or off. When followed by numbers it
specifies memory usage (number of bytes reserved for the default
memory usage, number of bytes for the heap, and the maximum heap size
in bytes).
The command line may specify filenames and options in any order,
although the options usually appear first:
QPL [options] filename [file ...]
If you specify multiple filenames, each file is processed
sequentially, using the same set of options for each.
NOTE: The defaults for the environment and the command-line compilers
are the same EXCEPT for the debug information and local symbol data
directives (/$D and /$L). By default, they are both ON in the
environment, and OFF for the command line.
The "QPL" Environment Variable
------------------------------
QPL.COM looks at the DOS environment area to see if the"QPL" variable
has been set. Use the QPL variable to specify a default set of
options. The syntax is the same as the QPL command line. For example:
SET QPL=/$R-,M- /UC:\QP\UNITS /IC:\QP\INCLUDES
QuickPascal uses the following priorities to process compilation
directions and options:
1. It looks at the source code (for any "{$...}" directives).
2. It looks at any command-line arguments (QPL.COM).
3. It looks at the QPL environment variable.
The QPL environment variable identifies the default options, but
directives in the source code have the final say.
Circular Referencing in Units
-----------------------------
Chapter 7, "Units," of "Pascal by Example" erroneously states that
QuickPascal does not allow some forms of circular referencing
(units A -> B -> C -> A). QuickPascal DOES allow circular referencing
in a unit's IMPLEMENTATION section (but not in the INTERFACE
section).
If You Plan to Use Turbo Pascal Units in QuickPascal
----------------------------------------------------
Although QuickPascal can compile virtually all Turbo Pascal source
code without modification, QuickPascal cannot use units compiled with
Turbo Pascal (.TPU files). To use an existing Turbo Pascal unit,
recompile the source code with QuickPascal.
No Overlay Unit
---------------
QuickPascal does not support an overlay unit.
Calling Interlanguage Procedures
--------------------------------
QuickPascal supports calls to procedures written in Microsoft
Assembler (MASM) or a compatible assembler, but does not support
calls to procedures written in any other language.
QuickPascal Linking Order
-------------------------
The memory map described in "Pascal by Example," page 150, is
incorrect. QuickPascal always links the System unit first, placing it
at the lowest memory position (memory offset 0). QuickPascal links the
remaining units in the order they appear in the USES statement.
Untyped Parameters in MSGraph
-----------------------------
The help system's summary of _RemapAllPalette, _GetImage, and
_PutImage all include variables without type declarations. This is
intentional. You can declare these variables as a variety of types
(as arrays, reals, etc.). Choose the one that best suits your
purpose. For example, large images are typically stored as arrays of
type Byte.
Turning On the Pascal Syntax Command
------------------------------------
By default QuickPascal displays .PAS and .INC files with the Pascal
Syntax command on (keywords, strings, comments, etc. appear in
different colors). Files with other extension are not displayed in
color (Pascal Syntax off), even if they contain Pascal programs.
Just choose the Pascal Syntax command (Edit menu) if you want to
see the program in different colors.
Correction to Book Examples
---------------------------
Chapter 14, "Using Fonts," of "Pascal by Example" contains an example
on page 220 in which _SetFont is checked for a return value of -1
(indicating an error). As a general rule, check for error values < 0
(as opposed to just -1).
The sample code fragment at the top of page 177 of "Pascal by Example"
(Chapter 13, "Using Graphics") contains a misplaced comma. Replace
the lines
_GetVideoConfig( ,vc );
Writeln( 'mode: 'vc.Mode );
with
_GetVideoConfig( vc );
Writeln( 'mode: ',vc.Mode );
On-Line Example Programs
------------------------
The REALG.PAS sample program in "Pascal by Example" differs from the
one in the on-line help system. The help version contains these
enhancements:
1. It resets the monitor to 43/50 line mode before making any
graphics calls.
2. An IF...THEN...ELSE statement in the main program prints a message
on the screen only if there is no acceptable graphics mode.
3. The program resets the monitor to its original state when the
program terminates.
The on-line version of ANIMATE.PAS differs from the version in
"Pascal by Example" on page 212. The on-line version compares the
size of the image against both MaxAvail and max_buffer, to ensure
that the heap has enough space.
The example program OBJECTS.PAS on page 234 of "Pascal by Example"
has been changed in the on-line version. In the book, the function
geo_shape.get_area incorrectly assigns Self.height to the function
name get_area. This has been corrected in the on-line OBJECTS.PAS
program.
Descriptions of the Disk-Based Sample Programs
----------------------------------------------
BIGMEM.PAS is a simple program that uses the unit BIGHEAP.PAS.
BIGHEAP.PAS redefines the GetMem and FreeMem procedures to allocate
and free memory blocks larger than 65520 bytes.
SORTDEMO.PAS is a program that illustrates several different sorting
algorithms.
OBJECTS.PAS is a simple program that uses the QuickPascal
object-oriented extensions.
GRDEMO.PAS is a graphics demonstration program that the use two
units, TURTLE.PAS (for turtle graphics) and MENU.PAS (for menu
input and output).
Selected Text Command Shortcut for International Keyboards
----------------------------------------------------------
QuickPascal supports the Selected Text command keyboard shortcut
CRTL+F3 in addition to the CTRL+\ shortcut shown on the Search menu.
Use whichever command is easier on your keyboard.
===============< Part 2: Recommendations and Limits >===============
If You Run QuickPascal Under DOS 4.X
------------------------------------
Computers that run QuickPascal under any version of DOS 4.X in the
43 line mode, and have ANSI.SYS installed, display only 25 lines on
the screen after leaving QuickPascal. The display remains in 43 line
mode, but only 25 lines appear before the display starts to scroll.
To return the display to its normal 43 line mode, type:
MODE CO80,43 (at the DOS prompt).
Special Instructions for QP Express
-----------------------------------
You may have difficulty running the QP Express Computer-Based
Training (CBT) program due to your video driver/graphics card
combination. Try the following:
1. Make a backup copy of the QP Express or QP Express/QP Advisor
disk. Use the backup copy for the remainder of this procedure.
2. On the backup copy of the QP Express or QP Express/QP Advisor disk
you will find files with the extension .VID. Each of these files
is a driver for a specific type of graphics card. The following
drivers support the indicated graphics cards:
ATT6300.VID For Olivetti and ATT PCs.
CGASNO.VID For CGA cards that produce a snow effect.
ERICSSON.VID For Ericsson PCs
HERC102.VID For the Hercules 102 card
HERC112.VID For the Hercules 112 card
If you use one of these computers/displays, rename the appropriate
driver to SCREEN.VID. For example, if you run an AT&T computer,
type: RENAME ATT6300.VID SCREEN.VID
3. You can now resume SETUP or run the CBT directly by typing: LEARN.
Storing Screen Images Larger than 65520 Bytes
---------------------------------------------
If you store screen images smaller than 65520 bytes you can allocate
the necessary memory with the GetMem procedure. If your image
requires more than 65520 bytes, you can allocate larger sections of
memory with the sample unit BIGHEAP.PAS. The sample program
BIGMEM.PAS shows how to call the unit's routines.
Maximum Number of Units
-----------------------
A program can use a maximum of 81 units.
Maximum File Size
-----------------
The documentation states that the maximum file size is 64K. The
actual maximum file size is 64K - 16 bytes.
MSGrUtil Unit
-------------
The MSGraph unit uses the MSGrUtil unit. For graphics to function
properly, make sure MSGRAPH.QPU has access to MSGRUTIL.QPU. To ensure
access, keep the two files in the same directory (the SETUP program
does this automatically).
Extending the Scope of Identifiers
----------------------------------
All identifiers (variable, constant, procedure, and function names)
can be "fully qualified" in order to extend their scope.
For example, if a procedure named 'Proc1' declares a variable A1, then
the scope of A1 is Proc1. If Proc1 contains a procedure called 'Proc2'
that also declares a variable A1, the value of A1 in Proc2 and the
value of A1 in Proc1 do not interfere with each other. The A1 in Proc1
normally has a scope limited to just Proc1. However, you can refer to
A1 (or any other variable) from Proc1 in Proc2 by using the fully
qualified name 'Proc1.A1'.
Chapter 7, "Units," in "Pascal by Example" indicates that you can use
this method to refer to procedure names, but does not indicate that
you can also extend it to all identifiers.
Block Indents
-------------
You can indent an entire block of code simultaneously by selecting
the lines to indent and pressing TAB. You can similarly outdent
by pressing SHIFT+TAB
Commenting Out Code
-------------------
Both { and } and (* and *) delimit comments in QuickPascal. If you
normally use { and } to delimit comments in your programs, use (* and
*) to quickly comment out large sections of code for debugging
purposes, or vice versa.