Losing global variable value

[Raymond Lyons]

A week or so ago in another thread I mentioned that I had experienced losing the value of a global variable. Martin Cole responded saying he also had experienced such a thing some time ago. Well, while doing heavy development work on an old app, I am now experiencing it again, pretty much on at least a daily basis. In this case the variable is the user's name and it is set in a logon script and it should be impossible for it to change until the next logon. I do see the logon user's name when I log on, so I know it is there at that point. I also occasionally notice it as I am testing the app. However, I do not notice when it goes to blank--I only notice that when I am looking at a record where it should have been written and notice that it is not there. Then I go elsewhere (e.g., the xbasic explorer) and note that it is in fact now blank.

Has anyone besides me and Martin experienced such a thing?

Any ideas as to how to figure out what could be happening? I am going to examine thousands of lines of xbasic code, but I can't imagine ever doing anything that would blank out this variable.

Ray Lyons

[martinwcole]

RE: Losing global variable value

Raymond, I hope you figure out the issue, as I depend on global variables. And i would like to know what can destroy one.

But a solution for you is to make it a constant. Also, if a script is trying to reset it somehwere, so long as you use an error handler script, you will get an error message when trying to reset a constant.

t=table.open("settings")
constant global name = t.name
t.close()

[csda1]

RE: Losing global variable value

Ray,

I can't imagine this ever happening, and have never experienced this behavior, however, I'd look at potentially redim and deletion of variables. Array redimensioning also would be an area I would look at closely.

Are there any eval() or eval_template() used that may have the wrong text string? How about forms with variables set to a global scope? It may also be potentially a scope setting issue, or places where you pass a pointer to the variables space.

You could use a timer event that would check the value of the global variable and stop operations (with a dialog box, perhaps displaying the time) it if it ever became blank or similar.

Regards,

Ira

[Steve Workings]

RE: Losing global variable value

This has happened to me for a couple, and I think I could say, several years. I've never studied it closely, but I seem to lose mine most frequently when use the set editor. My general experience is that table editing and, once in a long while, field rule editing may also be culprits (again, nothing concrete here -- just an accumulation of general undocumented observations). But the set editor is a definite culprit for me.

- Steve

[Raymond Lyons]

RE: Losing global variable value

Thanks Martin, Ira and Steve. Each of you has given me something to work on. I have done a bit more investigating and given what Steve said I am now very suspicious of the set editor being responsible for the loss. On this theory I had hoped that I as the a deveolper was the only one losing the value of the variable, and that is almost the case. The app was recently emptied and loaded with new records, so there are only 644 real live records to look at. Out of those only one was missing the user's name, which comes from the variable in question. That is both good and bad news. Good that it is only 1 out of 644 but bad because it really needs to be zero out of 644 because the user's are paid a significant commission on records with their name attached (thus at least one person would not be happy to hear of this problem!).

Anyway, this is just an update. If I discover anything more of interest I'll post it here.

Ray

[Raymond Lyons]

RE: Losing global variable value

An update: In developing, the value of the variable was bing lost any time I went into the set editor. And that was because many long years ago when the app was birthed I had for some reason made the variable global in the set editor, where of course it is ="". When I remove it from there (it was always dimmed global at logon anyweay), the value is no longer lost when using the set editor. Thanks Steve, for the clue.

This still leaves the question as to how one time out of 644 the value of the variable did not get written to a table, but that quite possibly had nothing to do with the value being lost, though that is still possible and something I need to look into some more.

Ray

[Steve Workings]

RE: Losing global variable value

Glad you found your answer. I lose the variable even though it's not defined in the set.

As for the data error, repeat after me:

"They're only computers - dumb computers."

If you're concerned about a critical piece of data, I'd suggest some code in the table's "CanSave" event or similar. If a value isn't what you expect, put up a dialog to collect it and/or inform the user of the problem.

- Steve

[Raymond Lyons]

RE: Losing global variable value

Good idea. As soon as I find a round to-it I'll do it!

Re: "Dumb computers" I recently ran into an example of how dumb they are. Would you believe they can't see that "REFINCO" and "REFINOC" are supposed to be the same thing? Hmm, with this font they are more obviously different. Maybe that will be my excuse for taking so long to catch it.

Ray

[Melvin Davidson]

RE: Losing global variable value

Just out of curiostity, since this occurs with the set editor,
is it possible you have defined global variables for the set with the same name as other global variables defined elsewhere?

[Raymond Lyons]

RE: Losing global variable value

Yes. I thought I made that clear 2 or 3 posts up. In any case I should never have dimmed it in the set since it had already been dimmed gloabl in the logon script. Why I did it in the set also--well that was so many years ago there is no telling. Certainly I was dumber about this stuff back then!

Ray