Shedding Some Light

In an effort to entice you to sit in on my Extending the Sedna Data Explorer session I have recorded a short teaser video, and have it posted on the Southwest Fox Video page. The same session will be given at the German DevCon in November.

Please take a look and let me know what you think.

I am looking for software that will convert AVI files to WMV (Windows Movie File) or SWF (Flash). Any recommendations?

We all take things for granted and I recently found renewed appreciation for the VFP compiler catching simple things. Over the last week I have been working on and off to track down an indexing issue brought to my attention by one of White Light Computing’s sub-contractors. It is an issue between VFP and FoxPro for DOS.

One of my test programs runs in FoxPro 2.6a DOS and had the following code:

llSeek1 = SEEK( “CRANE “, “test”, “lo_locn” )
llFound1 = FOUND()
llEOF1 = EOF()

I posted the code for a code review and it was revealed to me something I know: FoxPro 2.6a does not support the third parameter for the SEEK() function. FoxPro 2.6a for DOS and FoxPro 2.6a for Windows happily accept the line of code and ignore the extra parameters. I guess the FoxPro compiler figures this is a mistake on your part and is doing you a favor by ignoring the problem. In my case it was bad because I did not have the proper index tag selected and I was getting misleading results.

In VFP, the compiler catches extra parameters. If you add a fourth parameter to the SEEK() function VFP provides you some responsible feedback.

Compiling d:\devvfp9apps\junk\program1.prg
llSeek1 = SEEK( “CRANE “, “test”, “lo_locn”, “more?” )
Error in line 23: Too many arguments.

Compiler rules being tighten does cause pain initially, but in reality this is one of the best things the Fox Team did for us over the many versions released. I work in several versions of FoxPro and VFP these days, and understand the tweaks on the syntax is something I get burned on once and awhile. I really appreciate when the compiler saves my bacon.

One of the other things I commonly see with code I am working on is the ENDIF comments. For instance, sample code:

IF llCondition
llQueryOK = .T.
ELSE
llQueryOK = .F.
ENDIF llCondition

Initially looking a the ENDIF one might think this is invalid syntax (ok, maybe I was the only one {g}) and the developer forgot to put in the && inline comment. In reality, FoxPro knows there is no valid syntax after the ENDIF so the rest of the line is completely ignored at compile time. This happens in all versions of FoxPro.

We have been taking on quite a few projects over the last year and my preference is to recompile to VFP 9 so we support fewer versions of VFP compilers and runtimes, and I want to take advantage of the stability of VFP 9. The most common compiler error I see is the lack of commas separating variable declarations. This one drives me crazy. It is easy to fix for sure and VFP 9 is really good about pointing out the problem.

I am doing some research on a strange index issue today (likely a future blog post). Googling almost anything in VFP will link you to the single biggest FoxPro KnowledgeBase on the planet: Steven Black’s hosted Visual FoxPro Wiki. I wish I had a count of the number of times I visit the Visual FoxPro Wiki.

Today the topic I found extremely compelling is “CDX Corruption Checklist“. It is already marked as a three-star topic (highly rated). This topic did not help me solve my problem, but it was an excellent read.

My thanks to all involved in putting this one together.

GoDaddy hosts my personal Web site for cheap. Last week while on vacation they decided to move it to a new server, then asked *me* to test it. Sure enough: 401.3 Unauthorized due to ACL on resource. My research indicates it is a NTFS permissions problem.

Every time I navigated to the Web site I was prompted by a login screen. Sweet.

Yesterday I called GoDaddy’s normally excellent tech support from an airport as I was waiting for a flight. They told me I had to uninstall and reinstall FrontPage extensions, then republish the entire Web site. How is this related to a permissions problem?

OK, this is a hardware problem so I am not the authority here so I follow along. Uninstall and wait for 30 minutes. Fly home, eat dinner, reinstall. Same problem. Too tired from travel so I hit the sack. Get up, same problem. Have you heard how much I love hardware?

I call back today and get the same story. This time I mention I did a little research on the issue and it *could* be related to NTFS permissions. On and off hold for 30 minutes. GoDaddy tech support calls advanced tech support. New advice: reinstall FrontPage extensions and republish Web site. What?!?!

Sure enough it seem to work without the republishing of the Web site so I suspect some advanced tech support dude fixed the NTFS permissions in the 30 minutes it took to reinstall the extensions.

Anyway, I only meant to post a test post to see if I can. I can’t imagine slapping up a smoke screen to my customers while I fix something behind their back. GoDaddy should have tested my site before telling me it was ready. It would have saved me lots of time I don’t have.

One of my clients called me with a problem with one of their VFP 6 applications crashing. The application has been running in 30 locations for 10 years with very few changes. I did not develop this particular app, but did mentor the original developer and helped with the design. It is used by engineers. At the site it was working on one computer, but not the other three. The error is one of the more common ones: Function argument value, type, or count is invalid. (11)

The IT department no longer has fresh VFP expertise because they have moved on to a new development platform. They gave me a call hoping I could fix it immediately so the engineers could keep on working. They brought the data back, but could not reproduce the problem.

Fortunately the Visual MaxFrame error logging is decent. Unfortunately the customer does not compile in the debug code so I could determine the program, but not the line number or the actual code. I dug in using the error log and traced the code to the SYS(3050) command. In the startup of the application a call is made to a procedure that sets the amount of foreground memory to a percentage of the overall memory available on the machine. The calculation uses Windows API calls to get memory on the machine and then works through a formula. In this case we are talking about three new engineering workstations and they were loaded with 4GB of physical memory. The program was determining it could have a little more than 2GB of RAM. The VFP Help file does not indicate a limit even in the latest version, but apparently there is one.

So the lesson learned today is: do not to allow the setting of the SYS(3050) function be strictly calculated. I added code to pick the minimum of the original calculated amount and something less than 2GB. It is the first time I have used the VFP MIN() function in a long time.

I never hit this problem because I have a configuration item with the amount of memory to set. I know several developers use a formula to determine the amount of memory to allocate to VFP. If you are one of these developer you might want to check your formula to see if large amounts of memory could trigger this error.

All the details can be read on the Southwest Fox Blog.

I can say without question this was one of the most positive things I did yesterday. It is always fun listening to people be so excited about coming to Southwest Fox and hear how they think it will be a very beneficial experience. D.J. is coming to his first ever VFP conference! He is part of the Madison FoxPro Users Group (MadFox) so they are guaranteed at least $25 to help with the costs of running their user group too. I am looking forward to meeting him in person..

This was the third year in a row White Light Computing gave away a scholarship to someone coming to Southwest Fox, and the first year it was awarded to someone who is the sole person registered from their company.

Congratulation D.J.!

Only 99 days until we all meet in Mesa.

You heard it here first: I have changed my mind about speaking at Southwest Fox. Why? Providing better content and value to the people who pay good money to attend this terrific conference.

Oh, you might be thinking I am replacing myself with another speaker. Hmmm, trust me, it did cross my mind during the selection process because there were some terrific session ideas we had to turn away, but Doug and Tamar refused to let me “relax” during the conference while they are speaking {g}.

No, I am swapping out one session for another. I submitted a proposal to the other organizers to replace the Upsizing Wizard session with a new session I am developing called: “Using VFPX Components in Production Applications”. I have been having an absolutely great time working with some of the terrific components people like Emerson Stanton Reed, Carlos Alloatti, Kevin Ragsdale, Bo Durban, Cesar Chalom, and others have been creating. I have been presenting some of my implementation ideas I have at various user group meetings and the feedback has been exhilarating. I cannot wait to share this session with you at Southwest Fox. You will see live demonstrations of the VFPX components in real VFP production applications, and then I will show you all the nitty-gritty details to implement them.

More details here: Using VFPX Components in Production Applications

Hopefully those who were looking for the insight into the Upsizing Wizard are not too disappointed. Depending on the timing, I might include the white paper for this session on the conference CD as a bonus session.

ONLY 105 days until we meet in Mesa!