Friday, February 27, 2009

What's fixed in CA-Clipper 5.2c ?

The following information on the CA-Clipper 5.2c patch was extracted from 52ci.txt which came with the patch. This is an important patch as it fixes 22 known bugs !!!

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".

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 header file: #translate RLOCK() => DBRLOCK( RECNO() ) #translate DBRLOCK() => DBRLOCK( RECNO() )

2. Re-compile your program with the /u option, where 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.

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Welcome to Clipper... Clipper... Clipper

In 1997, then using Delphi 3, I had already created 32-bits Windows applications for HRIS, ERP and CRM. In 2007, using Ruby on Rails, an AJAX powered CRM site running on Apache & MySQL was created and I am now using Visual Studio .Net 2008 to create web-based projects and Delphi 7 for Win32 applications using SQL2005 & DBFCDX.

So, why then am I reviving the Original Clipper... Clipper... Clipper via a Blog as CA-Clipper is a programming language for the DOS world ? Believe it or not, there are still some clients using my mission-critical CA-Clipper applications for DOS installed in the late 80's and up to the mid 90's. This is testimony to CA-Clipper's robustness as a language :-)

With the widespread introduction of Windows 7 64-bits as the standard O/S for new Windows based PCs & Notebooks, CA-Clipper EXE simply will not work and it has become imperative for Clipper programmers to migrate immediately to Harbour to build 32/64 bits EXEs

Since 28th January 2009, this blog has been read by 134,389 (10/3/11 - 39,277) unique visitors (of which 45,151 (10/3/11 - 13,929) are returning visitors) from 103 countries and 1,574 cities & towns in Europe (37; 764 cities), North America (3; 373 cities) , Central America & Caribeans (6; 13 cities), South America(10; 226 cities), Africa & Middle-East (12; 44 cities) , Asia-Pacific (21; 175 cities). So, obviously Clipper is Alive & Well : -)

TIA & Enjoy ! (10th October 2012, 11:05; 13th November 2015)

Original Welcome Page for Clipper... Clipper... Clipper

This is the original Welcome Page for Clipper... Clipper... Clipper, which I am republishing for historical and sentimental reasons. The only changes that I have made was to fix all the broken links. BTW, the counter from is still working :-)

Welcome to Chee Chong Hwa's Malaysian WWW web site which is dedicated to Clipperheads throughout the world.

This site started out as a teeny-weeny section of Who the heck is Chee Chong Hwa ? and has graduated into a full blown web site of more than 140 pages (actually hundreds of A4 size pages) ! This is due to its growing popularity and tremendous encouragements from visiting Clipperheads from 100 countries worldwide, from North America, Central America, Caribbean, South America, Europe, Middle-East, Africa and Asia-Pacific. Thanx Clipperheads, you all made this happen !

What is Clipper ?

You may ask, what is this Clipper stuff ? Could Clipper be something to do with sailing as it is the name of a very fast sailing American ship in the 19th century ?

Well, Clipper or to be precise, CA-Clipper is the premier PC-Software development tool for DOS. It was first developed by Nantucket Corporation initially as a compiler for dBase3+ programs. Since then, CA-Clipper has evolved away from its x-base roots with the introduction of lexical scoping & pre-defined objects like TBrowse. As at today, the most stable version ofClipper is 5.2e while the latest version, 5.3a was introduced on 21 May 1996.

As at 11th November, 1996, an unofficial 5.3a fixes file was made available by Jo French. See the About CA-Clipper 5.3a section for more details. BTW, Jo French uploaded the revised 5.3a fixes file on 20th November, 1996.

Latest News

The latest news is that CA has finally released the long-awaited 5.3b patch on 21 May, 1997.

For 5.3b users, you must a take a look at Jo French's comments on unfixed bugs in 5.3b.

BTW, have you used Click ? If you're a serious Clipperprogrammer and need an excellent code formatter, Click is a natural choice. How to get it ? Simple, access Phil Barnett's site via my Cool Clipper Sites.

32-bits Clipper for Windows ?

Have you tried Xbase ++ ? Well, I have and compared to Delphi (my current Windows programming tool of choice), I'm still sticking to Delphi.

Anyway, you should visit the Alaska Home Page. Give it a chance and then draw your own conclusions !.

The Harbour Project

Is this the future of Xbase ? Take a look at at the Harbour Project

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