The LA Fox Developer Newsletter

July 2000

Undocumented (Can’t from page 3) This function returns “Diagnostic Mode Entered - SYS(1020) exits” in the status bar. These functions work and sometimes they don’t, depending on the version of Fox or VFP you’re running. This function used to slow down your Fox or VFP session tremendously. It doesn’t look like it has much effect now, though.

SYS(1022)

This function made it’s first appearance in version 1.02 of Fox. This function used to return “Diagnostic Mode Enabled” or “Diagnostic Mode Disabled” as a wait window. Now it doesn’t appear to do anything... These functions work and sometimes they don’t, depending on the version of Fox or VFP you’re running.

SYS(21 47483648)

This function returns a different value depending on which version of Fox or VFP you’re usirg. On VFP 6.0 SP3, this now returns the same value as SYS(0’ In some versions this would return “1”. Note that SYS(2 147483647) returns nothing. What’s the significance of SYS(2147483648)? This is the same number as 2 to the 31st power.

SYS(999)

There’s a standing bug in VFP 6.0 — run SYS(999, 4412) in the command window and note the duplicate H hot keys. That’s how it was found — by running through all the dialogs generated by this function... — BillAnderson

What does Sys(999) do?

SYS(999,n) brings up a bitmap image of the dialogs in VFP, presumably so screen shots can be taken or localization text can be inspected for fit. It serves no practical purpose. — StevenBlack

You can use the up and down arrow key to browse through all dialogs that are included in VisualFoxPro. I bet you find some you’ve never seen before. :) ChnstofLange

It shows dialogs all the way to SYS(999,n)where n=4507. Using

4508-4999 for n causes nothing to happen; 5000+ generates an

error.

JohnKoziol

Calling SYS(999,4507) on Windows 2000 build (2031) freezes VFP 6.0. — PaulBorowicz

I couldn’t find this documented anywhere. Where did you guys get this info? —ToddChandler

It’s not documented. Hence, the category. I started the category so I know it’s not documented. My real question is where do guys like John, Steven, and Paul get the answers. Do they have secret connections in the VFP syndicate? Is it expenmentation? I’ve only been working with Foxpro for about a year and there seems to be a lot of these types of “secret nuggets”. Is there a rule of thumb on how to find out this kind of arcane knowledge or is it just something that trickles out over years of using a product? The Wki seems like a good place to start a nugget repository. — ToddChandler

We pay attention to what ChnstofLange says on

CompuserveVFoxForum and on the UniversatThread :-). He’s

among the people who’s great for finding stuff like this. — StevenBlack

SYS(999,333) is interesting. It shows the help/about bitmap. Notice the “Application Security” button. — MichaelGEmmons

UNPACK(some parameter)

Now, can anyone figure out this function? My guess is that this is a secret function that MSFT uses to install VFP onto your hard drive. This function takes a parameter of some sort. If you don’t pass a parameter, VFP returns an error, so there’s error checking going on. See also: Microsoft Knowledge Base articleQg5307: “PRB: “Too Few Arguments” Error with Function Named UNPACKO”

LIST HISTORY

This command would list all the dBaselll+ interactive commands. If you used the TO PRINT option, this would go to the printer. The TO FILE option appears to “work” as well in VFP, in the sense that it doesn’t generate an error message.

LIST USERS

This command only returned results when one was using the dBaselll+ LAN Pack, returning a user list without stopping. BTW, these commands also “worked” on every version of the Macintosh product as well. Even FoxBase+/Mac?. At least it didn’t give an “Unrecognized command” error.

LOGOLJT

This command got one out of the dBaselll LAN Pack. This command did nothing without the LAN Pack and VFP does nothing with it either.

MODIFY VIEW (.vue file)

This command used to be an undocumented function — this command used to open the specified .Vue file, allowing one to, well, modify the view. This “capability” appears to have been completely dropped. So for those who say VFP has always had backward compatibility, remind them of this command. Now this command is used to open to View Designer to the seleced view within the current database. Nonetheless .VUE files are still supported in VFP. Try this:

SELECT 0 use (_Samples)+"\data\customer" ?DBFO

CREATE VIEW RatFace && makes RatFace.VUE CLEAR ALL

SET VIEW TO RatFace ?DBFO

— Steven Black

ON APLABOUT

This command was used in the Macintosh products to trap for the Help selection off the Apple menu.

ON MACHELP

(Con’t, page 5)

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