Dear CA-Clipper 5.2 Developer, This file contains:

      A. The instructions for applying the CA-Clipper 5.2c patch to any 
         North American version of CA-Clipper 5.2 including: 5.20, 5.2a 
         or 5.2b.  Please review these instructions carefully before 
         attempting to apply the patch.

      B. The problem resolutions contained in the CA-Clipper 5.2c patch.

      C. A technical note pertaining to a problem within the RLOCK() and
         DBRLOCK() functions.


==============================================================================
A. Instructions for patching 5.2 (any rev.) to 5.2c (rev. 204).

REQUIRED FILES FOR PERFORMING UPDATE:

   52CUS.EXE            A self extracting ZIP file that may be 
                        downloaded from the CLIPPER forum (library 0) 
                        on CompuServe. (GO CLIPPER).

   PATCH.EXE            Updating engine required for use with all 52C 
                        *.RTPs.  This file is also in Library 0 of the 
                        CLIPPER CompuServe forum.


CONTENTS OF 52CUS.EXE:

   INSTALL.EXE          Installation engine required for performing the 
                        CA-Clipper 5.2c installation patch.

   DISK.ID              Installation identification file.

   INSTALL.DAT          Installation script file.

   CLP52INC.LIF         Compressed update file for CLIPPER5\INCLUDE

   52CDBU.LIF           Compressed update file for CLIPPER5\SOURCE\DBU

   52COBJ.LIF           Compressed update file for CLIPPER5\OBJ

   52CRL.LIF            Compressed update file for CLIPPER5\SOURCE\RL

   52CSAMPL.LIF         Compressed update file for CLIPPER5\SOURCE\SAMPLE

   52CSYS.LIF           Compressed update file for CLIPPER5\SOURCE\SYS

   CLP52BIN.RTP         Update file for CLIPPER5\BIN

   CLP52LIB.RTP         Update file for CLIPPER5\LIB

   CLP52NG.RTP          Update file for NG

   52CUS.TXT            This file.


UPDATE PROCESS:

1.   o    Download the 52CUS.EXE file from Compuserve.

2.   o    Make sure that you have placed PATCH.EXE in a directory
          which is in your DOS path.

3.   o    Move to your CA-Clipper 5.2 directory.
               EXAMPLE: C:\> CD\CLIPPER5

4.   o    Backup your current version of CA-Clipper.

5.   o    If you have applied either the CA-Clipper 5.2a or 5.2b patch, 
          your BIN, LIB, INCLUDE and SOURCE\SAMPLE sub-directories may 
          contain prior versions of CA-Clipper 5.2.  These sub-directories 
          may cause the wrong version to be updated.  Therefore, you must 
          remove them from the CA-Clipper 5.2 directory structure before 
          applying the CA-Clipper 5.2c patch.  This can be accomplished 
          be either deleting them or moving them out the CA-Clipper 5.2 
          directory structure.  If you have not applied the 
          CA-Clipper 5.2a or the 5.2b patch, you may skip this step and 
          proceed to step 6.
             EXAMPLE: C:\CLIPPER5> del c:\clipper5\bin\backup
                      C:\CLIPPER5> rd c:\clipper5\bin\backup
                      C:\CLIPPER5> del c:\clipper5\lib\backup
                      C:\CLIPPER5> rd c:\clipper5\lib\backup
                      C:\CLIPPER5> del c:\clipper5\include\backup
                      C:\CLIPPER5> rd c:\clipper5\include\backup
                      C:\CLIPPER5> del c:\clipper5\source\sys\backup
                      C:\CLIPPER5> rd c:\clipper5\source\sys\backup

6.   o    Move to the disk drive and directory where the patch files are
          stored.
                EXAMPLE: C:\CLIPPER5> CD\52CUS

7.   o    Insert a blank formated diskette in the A: drive and move to it.
                EXAMPLE: C:\52CUS> A:

8.   o    Execute the 52CUS.EXE file.
                EXAMPLE: A:\> C:52CUS

9.   o    Execute the installation program and follow it's simple 
          instructions.
                EXAMPLE: A:\> INSTALL

10.  o    Compare the date and time stamps of the updated files against 
          the file list (below). If you have encountered a problem that 
          you are unable to correct, call your CA-Clipper Level-I 
          Technical Support representative.


11.  o    If you have applied the CA-Clipper 5.2c patch in a directory 
          other than the one into which you installed the original 
          CA-Clipper 5.2 version, you must make sure that your 
          PATH, INCLUDE, OBJ, and LIB environment variables have been 
          correctly set to point to the updated version of CA-Clipper.
          Example: 
                  (Scenario: You installed CA-Clipper 5.2 in C:\CLIPPER5
                  and later renamed the directory (or moved the files) 
                  to C:\CLIP52C.)
                  A:\ SET PATH=C:\CLIP52C\BIN
                  A:\ SET INCLUDE=C:\CLIP52C\INCLUDE
                  A:\ SET OBJ=C:\CLIP52C\OBJ
                  A:\ SET LIB=C:\CLIP52C\LIB

          NOTE: You should also change these settings in your AUTOEXEC.BAT file.

12.  o    Move to your DBU directory, define RTLINK's behavior and
          re-compile DBU.
          EXAMPLE:
                  A:\> C:
                  C:\NG> CD \CLIPPER5\SOURCE\DBU
                  C:\CLIPPER5\SOURCE\DBU> SET RTLINKCMD=
                  C:\CLIPPER5\SOURCE\DBU> RMAKE DBU

     o    Copy DBU.EXE to your BIN directory.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\DBU> COPY DBU.EXE C:\CLIPPER5\BIN

     o    Delete the executable and object files that were created 
          during the re-compilation process.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\DBU> DEL *.exe
                  C:\CLIPPER5\SOURCE\DBU> DEL *.obj

13.  o    Move to your RL directory, re-compile RL.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\DBU> CD \CLIPPER5\SOURCE\RL
                  C:\CLIPPER5\SOURCE\RL> RMAKE RL

     o    Copy RL.EXE to your BIN directory.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\RL> COPY RL.EXE C:\CLIPPER5\BIN

     o    Delete the executable and object files that were created 
          during the re-compilation process.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\RL> DEL *.exe
                  C:\CLIPPER5\SOURCE\RL> DEL *.obj

14.  o    Move to your PE directory, re-compile PE.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\RL> CD \CLIPPER5\SOURCE\PE
                  C:\CLIPPER5\SOURCE\PE> RMAKE PE

     o    Copy PE.EXE to your BIN directory.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\PE> COPY PE.EXE C:\CLIPPER5\BIN

     o    Delete the executable and object files that were created 
          during the re-compilation process.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\PE> DEL *.exe
                  C:\CLIPPER5\SOURCE\PE> DEL *.obj

15.  o    Move to your PLL directory, rebuild BASE52.PLL and BASE52.PLT.
          EXAMPLE:
                  C:\CLIPPER5\SOURCE\PE> CD \CLIPPER5\PLL
                  C:\CLIPPER5\PLL> RTLINK @BASE52

     o    Do not become alarmed if the message: "Undefined Symbols... 
          should be resolved at EXE generation" appears during this 
          step.

16.  o    The update process is now complete.
        

LIST OF CHANGED FILES:

     o    This is a list of all files that have changed since the 
          release of CA-Clipper 5.2.

     o    The files that have a date stamp of 03-15-93 and a time stamp 
          of 5:21am have been updated by the CA-Clipper 5.2a patch.

     o    The files that have a date stamp of 06-10-93 and a time stamp 
          of 5:22pm have been updated by the CA-Clipper 5.2b patch.

     o    The files that have a date stamp of 07-07-93 and a time stamp 
          of 12:00pm have been updated by the CA-Clipper API diskette.

     o    The files that have a date stamp of 08-06-93 and a time stamp 
          of 5:23pm have been updated by the CA-Clipper 5.2c patch.

     o    The files: DBU.EXE, RL.EXE, PE.EXE, BASE52.PLL and BASE52.PLT
          will will have the date and time stamp of when they were most
          recently re-built.

     o    All other files should have a date stamp of 02-15-93 and a 
          time stamp of 5:20am.  These are the files that have never 
          been updated by any of the CA-Clipper 5.2 patches.

     o    Directory of C:\CLIPPER5\BIN
          
          CLD      HLP     19677 06-10-93   5:22p
          CLD      EXE     54351 08-06-93   5:23p
          CLIPPER  EXE    200644 08-06-93   5:23p
      
          
     o    Directory of C:\CLIPPER5\INCLUDE
          
          CLIPDEFS H        1703 06-10-93   5:22p
          RULES    RMK      2312 07-07-93  12:00p
          EXTEND   API      2194 08-06-93   5:23p
          EXTEND   H         238 08-06-93   5:23p
          FILESYS  API      2652 08-06-93   5:23p
          GT       API      2734 08-06-93   5:23p
          INKEY    CH       8579 08-06-93   5:23p
          ITEM     API      1802 08-06-93   5:23p
          RDD      API     27714 08-06-93   5:23p
          STD      CH      51452 08-06-93   5:23p
          VM       API      1093 08-06-93   5:23p
          ACHOICE  CH        951 08-06-93   5:23p
          ERROR    API      2090 08-06-93   5:23p
          FM       API       811 08-06-93   5:23p
          RDDSYS   CH        342 08-06-93   5:23p
      
          
     o    Directory of C:\CLIPPER5\LIB
          
          CLD      LIB     80719 06-10-93   5:22p
          ANSITERM LIB     11809 06-10-93   5:22p
          SAMPLES  LIB     53891 06-10-93   5:22p
          DBFNDX   LIB     27175 06-10-93   5:22p
          NOVTERM  LIB     13345 06-10-93   5:22p
          PCBIOS   LIB     13857 06-10-93   5:22p
          TERMINAL LIB     13857 06-10-93   5:22p
          CLIPPER  LIB    513181 08-06-93   5:23p
          DBFNTX   LIB     38977 08-06-93   5:23p
          EXTEND   LIB    126905 08-06-93   5:23p
          DBFCDX   LIB    107993 08-06-93   5:23p
          

     o    Directory of C:\CLIPPER5\OBJ
          
          CT2PATCH OBJ      4703 03-15-93   5:21a
          NTXLOCK2 OBJ       302 06-10-93   5:22p
          CDXLOCK  OBJ      6679 08-06-93   5:23p
          

     o    Directory of C:\CLIPPER5\SOURCE\DBU
          
          DBUNET   PRG      8931 06-10-93   5:22p
          DBUCOPY  PRG     17556 08-06-93   5:23p
          DBUVIEW  PRG     67609 08-06-93   5:23p
          

     o    Directory of C:\CLIPPER5\SOURCE\RL
          
          RLDIALG  PRG     10626 06-10-93   5:22p
          RL       RMK       436 06-10-93   5:22p
          RLBACK   PRG     40489 08-06-93   5:23p
          RLFRONT  PRG     40165 08-06-93   5:23p
          

     o    Directory of C:\CLIPPER5\SOURCE\SAMPLE
          
          BROWSE   PRG     10294 06-10-93   5:22p
          TBDEMO   PRG     12398 06-10-93   5:22p
      
          
     o    Directory of C:\CLIPPER5\SOURCE\SYS
          
          FRMBACK  PRG     17966 08-06-93   5:23p
          FRMRUN   PRG     28512 08-06-93   5:23p


==============================================================================
B. Problems resolved by CA-Clipper 5.2c:


        1.  Fixed most instances of the DBFNTX/1210 error.

        2.  Fixed INDEXKEY() so that when it is called with an invalid 
            order argument it will no longer corrupt the data at memory 
            location 0000:0000 in dos and will no longer generate a 
            General Protection Error in Exospace.

        3.  Fixed CMEM.OBJ (in Clipper.lib) so that the malloc(), 
            _fmalloc(), free() and _ffree() memory allocation functions 
            will return the correct information.

        4.  Fixed VM Integrity error when evaluating detached code 
            blocks that are nested three or more deep.

        5.  Fixed VAL() so it no longer left justifys the result.

        6.  Fixed ACHOICE() so that it will not redraw the menu window 
            after returning from the user specified function unless:
                A. the user specified function changes the number of 
                   elements in the menu array.
                B. the user specified function returned the new return 
                   code of AC_REDRAW (which can be found in ACHOICE.CH 
                   and has the numeric value of 4).

        7.  Fixed the Expanded Memory Manager so it will not attempt to 
            use more than eight megabytes of EMM.  Currently, Clipper 
            can not take advantage of more than eight megabytes of EMM.  
            Please note that the printed documentation is incorrect.  
            This was the cause of many corruptions on systems that had 
            more than eight megabytes of expanded memory.

        8.  Fixed an incorrect calculation in _xvalloc() that caused the 
            Virtual Memory Manager to allocate 1K to much if the 
            requested size + 16 (in bytes) was an even multiple of 1024.

        9. Fixed an internal calculation that did not account for 
           overflow when converting a segment:offset address to an 
           absolute address.  This could only be encountered by calling 
           the VM API function:_xvalloc().

       10. Fixed several problems in the DBFCDX replaceable database
           driver.

       11. Fixed a compatability problem between CA-Clipper Tools-II and
           CA-Clipper 5.2x.  Developers using CA-Clipper Tools-II 
           noticed unresolved symbols at link time.  The CT2PATCH.OBJ 
           file will resolve these problems and should be included as an
           object on the link line.   Please note that CT2PATCH.OBJ is 
           only intended for use with CA-Clipper Tools-II, those not 
           using CA-Clipper Tools-II should not include this file in 
           their applications.

       12. Fixed DBU so that closing a file with an associated filter 
           will no longer cause a DBCMD/2001 error.

       13. Fixed DBU so that performing a replace will no longer cause a 
           "Lock Required" error.

       14. Fixed REPORT FORM so header will print when creating a report 
           whose width is greater than 254 characters.
    
       15. Fixed REPORT FORM so that it now ejects properly for groups.

       16. Fixed REPORT FORM so that double spaced forms will now print 
           properly.

       17. Determined that the EG_SYNTAX error in REPORT FORM was not 
           caused by an empty database.  It was caused by the absence of 
           a field name for the report.  This is the correct behavior.

       18. Fixed REPORT FORM so that it will respect the "SUMMARY ONLY" 
           option when requested.

       19. Fixed REPORT FORM so that it no longer prints an extra form 
           feed after the report is completed.

       20. Fixed RL so that it will save entered data from all entry 
           screens instead of only the current display screen.

       21. Fixed RL so that it will no longer save the rightmost column 
           when it is empty.

       22. Fixed RL so that it accepts "T" or "F" in it's question 
           fields.  It previously was limmited to "Y" or "N".



==============================================================================
C: Technical Note: RLOCK()/DBRLOCK() problem


   o Problem:  
        RLOCK() and DBRLOCK() (without any parameter) will not reliably 
        lock a record under certain circumstances, even though their 
        return values (.T.) indicate success.  This occurs when locking 
        a record in the child database of a relation, after the record 
        pointer has been repositioned by a SEEK or GOTO, but before the 
        data has been accessed.


    o Solution:  
        A workaround for this problem is to use DBRLOCK( RECNO() ) 
        instead of RLOCK() or DBRLOCK().  A simple way to implement this 
        is:

        1. Add the following statements to a copy of the std.ch header 
           file: 
                      #translate RLOCK() => DBRLOCK( RECNO() )
                      #translate DBRLOCK() => DBRLOCK( RECNO() )

        2. Re-compile your program with the /u<file> option, where
        <file> is the modified STD.CH file.  


    o   EXAMPLE:
                  use child shared new
                  set index to childntx
                  use parent shared new
                  set relation to FieldOne into child
                  goto 2
--------------->  if ( rlock() )  // change this rlock() to dbrlock(recno()) 
                     replace child->FieldTwo with parent->FieldTwo
                  endif
                  close data
                  return


    o Note:  
        This is a temporary workaround while a solution for the problem is
        being worked upon.



==============================================================================
==============================================================================
