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    SECTION 17 - TP/BP DOS Programming

    This document contains information that is most often provided
    to users of this section.  There is a listing of common
    Technical Information Documents that can be downloaded from the
    libraries, and a listing of the five most frequently asked
    questions and their answers.

    TI1184   Overview of Borland Pascal 7.0 and Turbo Pascal 7.0
    TI1722   Declaring an array on the heap
    TI1760   Creating a temporary stack in real or protected mode
    TI1171   Problem Report Form
    TI1719   Booting Clean
    TI432   Printing graphics to an HP LaserJet
    TI433   Printing graphics to an Epson
    TI407   Using the serial port in a Pascal application
    TI152   Interupt handler for 3.X and lower
    TI226   Async routines for versions 3.X and lower
    TI232   Absolute disk read for version 3.x and lower

    LC2P01.FAQ   Linking C to Pascal Frequently Asked Questions
    EZDPMI.ZIP   Unit encapsulating common DPMI requests for
                 protected mode programming
    BIGSTU.PAS   How to cope with memory allocations > 64K
    PASALL.ZIP   Collection of Technical Information Sheets from
                 1986 on
    NEWRTM.ZIP   Latest RMT.EXE and DPMI16BI.OVL
    MOUSE.ZIP    General purpose mouse unit for text/graphic modes

    Q.   "How do I link an object file that is a library of
         functions created in C?"

    A.   Download the file "LC2P01.FAQ.  The C run-time library is
         needed by the object file.  Since Pascal can't link the C
         RTL as is, you will need the RTL source and will need to
         modify it so that it can be linked by TP.

    Q.   "How do I get the ASCII key numbers for the Arrow keys?"

    A.   Below is a short program that reveals this information.

         program DisplayAscii;
         uses Crt;
         var
           ch:char;
         begin
           repeat               { repeat until Ctrl-C }
                ch := Readkey;
                Write(Ord(CH):4);
           until ch = ^C;
         end.

         The program can be terminated by pressing Ctrl-C.  You'll
         see that keypresses such as UpArrow actually generated two
         bytes:  a zero followed by the extended key code.

    Q.   "Why do I get runtime error 4 while using the following
         line:  reset(InFile)?"

    A.   The error message means that you have run out of file
         handles.  The FILES= statement in your CONFIG.SYS doesn't
         change the fact that a process can, by default, open a
         maximum of 20 files (and DOS grabs 5 of those).  The
         SetHandleCount() API function can be used to increase the
         number of handles useable by your application.

    Q.   "I am using overlays with BP7 with Objects.  If Overlay A
         calls a procedure or function in Overlay B, does Overlay A
         stay in memory while Overlay B runs?  Or does Overlay B
         wipe out Overlay A, and when Overlay B finishes, it reloads
         Overlay A?"

    A.   It depends on the size of the overlays and the size of the
         overlay buffer you set up.  In general you can think of the
         overlay buffer as a pool of memory where overlaid units can
         be stored.  Every time you call a routine in an overlaid
         unit, that overlay is loaded into the buffer.  If the
         buffer is already full, then the oldest unit in the buffer
         is discarded to make room for the new one.  If you've got a
         small overlay buffer and large overlaid units, they may
         well kick each other out as they load.  If you've got a
         large overlay buffer the program may well keep everything
         in memory the entire time.

    Q.   "I am getting DosError = 8 when using EXEC() to execute a
         program from within my program.  How do I correct this?"

    A.   DosError = 8 means that there is not enough memory
         available to run the program being EXEC'ed.  Normally your
         program grabs all available memory and doesn't leave any
         for the program being EXEC'ed.  Be sure to use the $M
         directive which minimizes the memory required by your
         program.

    Q.   "I am getting DosError = 2 when using EXEC() to copy a
         file from one directory to another.  The file does exist
         and the command line is correct.  What is the problem?"
    A.   You might have assumed that because COMMAND.COM is on your
         path, EXEC will find it.  Nope.  EXEC needs the full path
         name.  You can use GetEnv('COMSPEC') to get the value of
         the environment variable COMSPEC which should be the full
         path.

    Q.   "Does Turbo Pascal run in Super VGA modes?"

    A.   Yes, if you have a VESA compatable video card you can use
         the VESA16.BGI file to get high resolutions such as 1024X768
         or 800X600. If you also want 256 color support, you should
         turn to a third party solution. There are some helpful
         files, including freeware drivers, available here on the
         forum.

    Q.   "How can I print my graphics code?"

    A.   Download the files labeled TI432.ZIP and TI433.ZIP from
         the libraries. Additional support is available from third
         party vendors. You could pose a question in the forum asking
         for recommendations regarding third party graphics support
         for printing.

    Q.   "When will Borland upgrad the GRAPHICS TOOLBOX?"

    A.   The GRAPHICS TOOLBOX is no longer available from Borland in
         any form, and there are absolutely no plans to upgrade it.
         It should, however, recompile with recent versions of
         Pascal including Versions 6.0 and 7.0.

    Q.   "How can I use BGI calls in Windows?"

    A.   Windows is a graphical operating environment, so there is
         no longer any need for the BGI when programming Windows. You
         will find that Windows has built in support for graphics
         that is much superior to anything available in the BGI unit.
         To get started, try using using the manuals and on-line docs
         to read about the Windows GDI.

    Q.   "How can I add a mouse to my Graphics programs?"

    A.   Outside of Windows and Turbo Vision, Borland offers no built
         in support for the mouse in your programs. However, adding
         mouse support is extremely simply. Those who know ASSEMBLER
         can add mouse support with the INT33 interface, others will
         find MOUSE libraries available here in the CIS libraries.

    Q.   "Are any of the ToolBox programs that shipped with versions
         3.0 and 4.0 still available.  For instance, can I get an
         upgraded copy of the Database ToolBox or the Editor
         ToolBox."

    A.   No. These programs are no longer in any form from any
         company. If you want to get a copy of them, you would need
         to purchase them from a current owner.

    Q.   "Can the ToolBox programs be used from version 7.0?"

    A.   It depends. As a rule, the answer is yes, all you need to do
         is recompile and they will run fine. This is totally
         fortuitous, however, and Borland has, and will, do nothing
         to update these programs. See TI1728 for help upgrading the
         Editor ToolBox.

    Q.   "How can I convert my Turbo Pascal 3.0 program to version
         7?"

    A.   There is a file called up UPGRADE.ZIP which is available on
         the forums. This can help in the process of upgrading the
         files. Most of the code from version 3.0 will run fine under
         7.0, but not all of it.

    Q.   "When I use the Turbo Vision editors unit from Version 6.0 I
         never see the numbers 3, 4, 6 and 7 when I try to type them
         in."

    A.   This was a bug in the first version of TP6.0. The fix is
         available in EDITOR.PAT, found in LIB1.

    Q.   "What ever happened to FreeMin and FreePtr?"

    A.   These Turbo Pascal 5.x identifiers are no longer used by the
         heap manager.  Simply delete references to FreeMin from your
         code. If you're using routines that use FreePtr to compress
         the heap or perform other implementation-dependent
         operations on the heap, you'll need to update these
         routines. (If you just need to lower the top of memory in
         order to do an Exec, you can call the SetMemTop procedure
         from the Turbo Vision Memory unit.) See the Programmer's
         Guide for more information about how the heap manager
         works.

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