ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/WINDOWS/PROGRAM/BC_CDK.ZIP/CDK_BC.TXT

Text File | 1991-09-01 | 22.4 KB | 578 lines

                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          I wrote this description to help anyone using Borland's C++
          compiler and Integrated Development Environment (IDE) to create
          custom controls for use with Microsoft's Visual BASIC.  The MS
          CDK (Control Development Kit) has a series of example programs
          that were written to work with Microsoft C version 6 or later.
          This document should help you get them to work using Borland's
          development products.

          This document assumes that you have purchased the MS CDK product.
          I make reference to specific line numbers within the files that
          were shipped to me with version 1.0 of that product.  When
          working with Borland's IDE, you can tell what line that you are
          currently editing by referencing the numbers in the bottom left-
          hand corner of the active edit window.  The numbers shown there
          appear in the format:

                          <line number> : <column position>

          for example:
                                        25:32

          which says that your cursor is on the 32nd character of line 25.

          In this document, I also assume that you have installed your
          Borland C++ product in the drive\subdirectory C:\BORLANDC.  Also
          that after installing the CDK, you have copied the file VBAPI.LIB
          to C:\BORLANDC\LIB and the file VBAPI.H to C:\BORLANDC\INCLUDE.

          While experimenting with this code, I created a subdirectory
          called TEMP under the directory for each control, copied all
          files for that control there, and edited the copies.  It is NEVER
          advisable to edit your original copies of anything.  Also
          remember that whenever you are coding at a systems-level, you
          should save your code frequently.

          If you have any comments, suggestions, or neat VBX files, please
          feel free to drop me a line in my Compuserve mailbox, or at my
          humble homestead at 1188 Morgan Ave, Williamsport, PA 17701.

          Throughout this document, I mention products and programs that
          are protected by some sort of legal nonsense or another, and I
          hope I can appease all legal-eagles by saying that any Borland
          product mentioned is trademarked and legally protected by Borland
          International Inc. of Scotts Valley, CA.  Any Microsoft product
          is trademarked and legally protected by Microsoft Corporation of
          Redmond, WA.  Anything done by you using the descriptions here
          should make neither them (nor me) liable for any silliness that
          might prevail.








          Brent K. Langley  Compuserve Userid 70312,2142             Page 1


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          GETTING THE CDK TO WORK:

          I have found that in getting the CDK code to work with the IDE
          there are 8 steps that I had to follow:

          1)   Change WINDOWS.H
          2)   Copy and Rename LibInit.Obj to C:\BORLANDC\LIB\C0VBINIT.OBJ
          3)   Create a Project file (.PRJ) to create the VBX/DLL file
          4)   Change CCINIT.C to take advantage of changes in WINDOWS.H
          5)   Handle any syntax errors in demo code
          6)   Handle any language incompatibilities in code
          7)   "Make" Project from IDE
          8)   Rename (or Copy) xxxxxxxx.DLL to xxxxxxxx.VBX

          Steps 1 and 2 from above only need to be done once.  Steps 3 and
          4 need to be done for every project, but follow the same steps.
          Steps 5 and 6 will be addressed separatly for each of the three
          example programs that need fixing.  Steps 7 and 8 let you put all
          of the pieces together.

          STEP ONE:  CHANGE WINDOWS.H

          The normal startup code for a DLL does a little processing and
          then calls your function called LibMain.  In a .VBX file, we have
          to replace the normal startup code with a modified routine that
          passes some extra information to our control's LibMain.  This
          means that the format for calling a VBX's LibMain is different
          from a normal DLL's LibMain.  This causes no real hassle to
          MSC/SDK developers because Microsoft doesn't include a function
          prototype in their version of WINDOWS.H for LibMain, however,
          Borland does.  And when Borland's compiler sees the CDK version
          of the LibMain function, it stops compiling with an error.

          We could just remove the function prototype for LibMain from
          Borland's WINDOWS.H, but it will help us with our syntax checking
          if we leave it there.  My solution is to define a constant called
          _CDK before the #include of WINDOWS.H.  Then have WINDOWS.H
          determine the existance of this defined constant to decide
          whether to use the CDK or normal version of LibMain.

          To do this, load C:\BORLANDC\INCLUDE\WINDOWS.H and then press
          Ctrl-PgDn to go to the bottom of the file.  Move your cursor up
          to about line 3473, and you should see Borland's function
          prototype for LibMain.  I changed this part of the code to be:

          #ifndef  _CDK
          int FAR PASCAL LibMain ( HANDLE, WORD, WORD, LPSTR );
          #else
          BOOL FAR PASCAL LibMain( HANDLE, HANDLE, unsigned short );
          #endif

          I used "unsigned short" instead of USHORT for the third parameter
          of the CDK version of LibMain because USHORT isn't seen in a
          typedef statement until the file VBAPI.H is #include'd later.


          Brent K. Langley  Compuserve Userid 70312,2142             Page 2


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          STEP TWO:  RENAME LIBINIT.OBJ TO C0VBINIT.OBJ

          Page 20 of the CDK Guide explains that LIBINIT.OBJ contains
          initialization code to replace the code from the file
          LIBENTRY.OBJ that is normally linked into DLL projects first.  So
          we must ensure that the code from LIBINIT.OBJ is linked before
          any other code in our projects.

          On page 141 of Borland's C++ User Guide, we find the section of
          the project manager chapter titled "Overriding Libraries" states
          that we can have our own startup file linked first, if:

               1)   its name starts with C0 (the letter C followed by zero)
               2)   it is placed as the first file in the project.

          We'll worry about making a project file in a minute, but for now,
          lets give LibInit.OBJ a new name to conform with step one from
          above.  While we're at it, lets also move it to a standard
          location (since the CDK manual says that this code would seldom
          need to change.)  If LibInit.OBJ is in your current directory,
          type:

                    COPY LIBINIT.OBJ  C:\BORLANDC\LIB\C0VBINIT.OBJ

          You could call it anything you want (so long as it starts with
          "C0") but since it contains the Visual Basic INITialization code,
          I thought that this name was appropriate.

          STEP THREE:  CREATE A PROJECT FILE

          For each control, you will make a project file that looks similar
          to the following:

                              C:\BORLANDC\LIB\C0VBINIT.OBJ
                              C:\BORLANDC\LIB\C0DC.OBJ
                              C:\BORLANDC\LIB\VBAPI.LIB
                              CCINIT.C
                              program.DEF
                              program.RC
                              program.C
                              .
                              . (any other program files or libraries)
                              .

          For example, the project for the CNTR control would look like:

                              C:\BORLANDC\LIB\C0VBINIT.OBJ
                              C:\BORLANDC\LIB\C0DC.OBJ
                              C:\BORLANDC\LIB\VBAPI.LIB
                              CCINIT.C
                              CNTR.DEF
                              CNTR.RC
                              CNTR.C



          Brent K. Langley  Compuserve Userid 70312,2142             Page 3


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          STEP THREE: CREATE A PROJECT FILE (continued)

          The file C:\BORLANDC\LIB\C0DC.OBJ listed in the above projects is
          the normal startup code file for Borland C (that has been
          superseded by C0VBINIT.OBJ) and should appear immediately after
          C0VBINIT.OBJ in your project file.  This file should actually be
          C0Dx.OBJ where "x" indicates your memory model that you are
          compiling with.  Since I used the "Compact" memory model for
          compiling my projects, this is C0Dc.OBJ in my code examples.

          Since a VBX file is a type of DLL, you should let the project
          manager know that you will be creating a DLL.  You can do this by
          typing Alt-O to activate the Options menu.  Type A to select your
          Application type, and then type D to select DLL.  Now when you
          save your project, this information will be stored with it.

          Besides the interactive way of building a project, you could make
          a batch file to create your project files, or you could copy this
          text to a .PRJ file, but then remember to run PRJCNVT to change
          the old-style text project file to Borland's new project file
          format.

          An example .BAT file called MAKEPRJ.BAT might contain:

                    @ECHO OFF
                    IF "%1"=="" GOTO ERROR
                    ECHO C:\BORLANDC\LIB\C0VBINIT.OBJ > %1.PRJ
                    ECHO C:\BORLANDC\LIB\C0DC.OBJ    >> %1.PRJ
                    ECHO C:\BORLANDC\LIB\VBAPI.LIB   >> %1.PRJ
                    ECHO CCINIT.C                    >> %1.PRJ
                    ECHO %1.DEF                      >> %1.PRJ
                    ECHO %1.RC                       >> %1.PRJ
                    ECHO %1.C                        >> %1.PRJ
                    PRJCNVT %1.PRJ
                    GOTO END
                    :ERROR
                    ECHO You must specify a project name
                    :END

          This uses the program PRJCNVT.EXE in your C:\BORLANDC\BIN
          subdirectory (probably in you PATH) to convert from a text .PRJ
          file to Borland's new project file format.  The first ECHO
          statement creates a new .PRJ file, and the rest of the ECHO
          statements append their line of text to this file.  The file is
          named using whatever you specify on the command line after the
          word MAKEPRJ.  For Example:

                                    MAKEPRJ  CNTR

          Would make the project example shown on the previous page and
          name it CNTR.PRJ.  Remember then to set the Alt-O-A-D options
          when you load this into the IDE.




          Brent K. Langley  Compuserve Userid 70312,2142             Page 4


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          STEP FOUR:  CHANGE CCINIT.C

          In step one, we modified WINDOWS.H to allow correct function
          prototyping of the LibMain function.  In the file CCINIT.C we
          will take advantage of this change.  This is the file where our
          version of LibMain is declared, so we want WINDOWS.H to use the
          CDK version of the prototype.

          This is pretty simple, all you need to do is to include the line:

                                    #define _CDK

          before the #include <windows.h> statement in the file CCINIT.C.

          I suggest that you type over line 6 in this file which is
          currently blank.  This will preserve the line numbers for the
          rest of the code.  CCINIT.C is very similar for each of the
          example programs in the CDK, but each does vary slightly.  Please
          make this change for every sample control project in the CDK.

          STEP FIVE:  HANDLE SYNTAX ERRORS
          STEP SIX:  HANDLE ANY LANGUAGE INCOMPATIBILITIES

          CIRCLE1, CIRCLE2, and PUSH have no further problems so you can
          continue with steps seven and eight for them.

          However, there is still some work that needs to be done with the
          files for CIRCLE3, CNTR, and PIX.  I prefer to address the
          problems for each of these programs separately, so please see
          their individual descriptions on the following pages.


          STEP SEVEN:  MAKE PROJECT

          You're just about done!  Press F9 and the IDE will create your
          DLL file.  If you prefer to use Borland's MAKE utility, you can
          convert your .PRJ file from step three (above) to a .MAK file
          with the Borland utility PRJ2MAK and then edit this make file to
          tailor it to your own specifications.

          STEP EIGHT:  RENAME .DLL FILE TO .VBX

          The IDE's project manager will create a file with the same
          filename as that of your .PRJ file.  The resulting file's
          extension will be .DLL but the Visual BASIC system will be
          expecting a Visual Basic eXtension file.  To accomodate Visual
          BASIC, just RENAME (I prefer to COPY)  name.DLL to name.VBX

          That's all there is (as if it isn't enough!)  Now you can load
          Visual BASIC and select Alt F D  for File Add-file and specify
          your .VBX file.





          Brent K. Langley  Compuserve Userid 70312,2142             Page 5


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



                                       CIRCLE3

          In addition to following the steps described above (such as
          putting the #define _CDK in CCINIT.C) CIRCLE3 has some
          compatibility problems:

          CIRCLE3 PROBLEM 1:

          On line 114 of CIRCLE.C there is a call to VBCreateHsz that uses
          the new MS C v6 type keyword "_segment".  My info on this keyword
          comes from an article in the March 1990 issue of Microsoft
          Systems Journal by Noel J. Bergman.  While describing the new (at
          that time) version 6 of MS C, he describes briefly, on page 58,
          the concept of "based pointers" and the function of _segement.

          He says: "When _segment is used to cast a near address, the
          result is the current value in DS" which can be obtained in BC++
          by specifying _DS or FP_SEG( (void far *) addr ).   He continues:
          "If the address is a far address, the result is the segment for
          that far address."  You can use the FP_SEG( addr ) macro in dos.h
          to get this value.

          A consistent way to handle both cases would be to use the FP_SEG
          macro and cast (void far *) on the pointer.  For example:

                             FP_SEG( (void far *) addr )

          Or, since the macro does this casting for you internally, you can
          abbreviate this as just:
                                    FP_SEG( addr )

          A side note:  when looking in the include file dos.h I found that
          FP_SEG is using a cast operation with the word _seg !?!   What is
          that?? Is it the same as _segment ??  It doesn't seem so.  Since
          I couldn't find it in the documentation, lets play it safe and
          stick with FP_SEG.  Although, if you are converting a MAJOR
          project, you could speed up the conversion by doing a global
          search and replace:  changing all

                                      (_segment)
          to
                             (void _seg *)(void far *)


          Using FP_SEG is easier to read (I think), and a little more
          portable.  The choice is up to you, but for this example, lets
          change line 114 of CIRCLE.C to read:

                     hsz = VBCreateHsz( FP_SEG(hctl), (LPSTR)lp);

          and then put the #include <dos.h> on the blank line between the
          includes for <windows.h> and <vbapi.h>  (this will preserve line
          numbers for the further editing that we have to do...)



          Brent K. Langley  Compuserve Userid 70312,2142             Page 6


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



          CIRCLE3 PROBLEM 2:

          In line 406 of CIRCLE.C, the reference to FlashDlgProc is meant
          to pass the address of a certain type of function to the function
          VBDialogBoxParam. It's function prototype on line 423 is:

           BOOL FAR PASCAL _export FlashDlgProc(HWND, USHORT, USHORT, LONG)

          but what is required for VBDialogBoxParam (on line 309 of
          VBAPI.H) is the type FARPROC that is defined on line 151 of
          WINDOWS.H as:

                        typedef int (FAR PASCAL * FARPROC)();

          OK, so all we need to do is cast this FARPROC type on the
          function FlashDlgProc.  Change line 406 of CIRCLE.C to read:

          VBDialogBoxParam(hmodDLL, "FlashDlg", (FARPROC)FlashDlgProc, 0L);

          Now your CIRCLE3.PRJ should compile cleanly.  Remember to rename
          (or copy) CIRCLE3.DLL to CIRCLE3.VBX  then fire up Visual BASIC
          and try it out!


































          Brent K. Langley  Compuserve Userid 70312,2142             Page 7


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



                                         CNTR

          CNTR, the counter control uses "based pointers" in a couple of
          its modules so there is some conversion that needs to be done,
          but there is an error (BUG??) in CCINIT.C that we must fix first.

          In CCINIT.C on line 45, the function modifier "PASCAL"  is
          missing from the definition of the function LibMain, so change
          this line from:
                                   BOOL FAR LibMain
          To:
                               BOOL FAR PASCAL LibMain

          Also, at the top of CCINIT.C (line 6, for example) remember to
          place the statement:
                                    #define  _CDK


          In CNTR.H and CNTR.C we need to remove the based pointer
          references and replace them with their equivalents in terms of
          far pointers.  I'm not sure why Microsoft added this based
          pointer complexity to this program, unless its that they felt
          that it would make the code run faster (using 16 bit pointers
          rather than 32 bit.)  But I don't think that this is the type of
          application that would benefit from the added complication.

          In CNTR.H we have some stuff to clean up.  Lines 26 through 34
          and also line 54 should be commented out as shown below:

               //   _segment  segCntr;
               //   #define BP _based(segCntr) *      // based pointer
               //   #define BH BP BP                  // based handle
               //   typedef VOID BH BHVOID;           // void handle
               //   typedef CHAR BH BHSTR;            // handle to a string

               //   #define CNTRDEREF(hctl)  ((PCNTR)(VOID *) ...

          and then change line 52 from:
                              typedef  CNTR  BP  PCNTR;
          to:
                              typedef  CNTR far * PCNTR;


          In CNTR.C comment-out line 53 as shown below:

               //   segCntr = (_segment) hctl;

          and change line 54 from:
                               pcntr = CNTRDEREF(hctl);
          to:
                            pcntr = VBDerefControl(hctl);

          Now CNTR should compile ok.  Rename CNTR.DLL to CNTR.VBX an go!



          Brent K. Langley  Compuserve Userid 70312,2142             Page 8


                             Using Borland C++ IDE with
               the Microsoft Visual BASIC Control Development Kit (CDK)



                                         PIX

          Remember to put the line:

                                     #define _CDK

          on line 6 (the blank line above #include <windows.h>) in the file
          CCINIT.C as described in step 4 (above).

          Lines 81, 85, and 109 of PIX.C use the non-Borland _segment type
          for casting as described for CIRCLE3 (above).  On each of these
          lines modify reference in the code for

                           (_segment) hctl

          to appear like:

                         FP_SEG( hctl )

          and place the line

                           #include <dos.h>

          at the top of the file PIX.C.

          Now this control should compile and link cleanly.  Remember to
          rename the resultant .DLL file to a .VBX file before you load
          Visual BASIC and try it out.

          --------------------------------------------------------------

          Well, I hope this made enough sense to get you going.  I tried to
          not only tell you what to do, but to also tell you where in the
          various references that I found my information.  I hope it helps.

          Also, I can't emphasize enough, for you to save your programs
          often.  A small mistake in your code can cause a Windows
          Unexpected Application Error (UAE) and either kick you completely
          out of Visual BASIC, kick you out of Windows, reboot your
          machine, or freeze your machine.  I have encountered all of these
          battle scars, but I survived and you will too!  Have fun....Brent















          Brent K. Langley  Compuserve Userid 70312,2142             Page 9