Random errors: what can cause them

Beware that I'm listing here problems that I encountered, but it doesn't mean that these problems happen all the time or under all the operating systems. I'll try to describe them as precisely as I can, but you should use this information only as a basis for your own investigation when you encounter a random problem...

Another thing is that this list concerns WinDev, but you could have the same kind of problems in any language... What I'm listing here is not a list of WinDev bugs, but more a list of things that you shouldn't do in your programs, and it happens that your programs are written in WinDev...

What is a random error? If you don't know, you are lucky enough to never have the problem before... But in some case, you can have your WinDev project behaving normally 99% of the time, and from time to time, without any specific and visible cause, generating an error message... Let's be clear, this is NOT a WinDev specific problem, you can have this kind of problems with about nearly ANY development tool... I am just going to list and explain here all the causes I found for this kind of problem in WinDev Clearly, the following cases are not sorted by anything, nor importance neither frequency... It always depends of your code... A random error can manifest itself by a normal WinDev error message (of course, this message is not related to the real problem, or it would be easy to fix), a GPF, or even a sudden disappearance of the executable without any message...

fRead of N bytes in a smaller string: (october 2005)
The fRead instruction allows you to read N bytes at any position in to a direct file... Depending of ... ---MORE---

Multitask: (october 2005)
I didn't test this in WinDev 7/8/9, but under WinDev 5.5, you can achieve some... ---MORE---

Missing iEndPrinting: (october 2005)
When you use some direct printing instructions in your code, like iCreateFont or iFont, and... ---MORE---

Window or Report name length: (october 2005)
This one happens only under WinDev 5.5: if you name some windows or report with a... ---MORE---

Class method name and file field name lengths: (october 2005)
Under WinDev 5.5, a class method name is supposed to support up to 30 characters, but... ---MORE---

Printing in the margins: (october 2005)
Nearly every printer has a technical margin at least on some of the paper sides. What am I... ---MORE---

Printing on no printer: (october 2005)
I added this one in the list, but it can not really be considered random... In fact if ---MORE---

Using UpdateWindow API call: (october 2005)
Of course, not everybody uses UpdateWindow in the first place... A lot of developers don't even ---MORE---

Not mapped network drives: (october 2005)
An old problem that you should better know about: under w98, if you do intensive work on a ---MORE---

Closing the calling window: (october 2005)
Once again, it's a gray area and something that is easy to find in simple cases... But when you are ---MORE---

Deleting twice: (october 2005)
Clearly, deleting a dynamic object twice is a bad idea. But when your code becomes complex, and ---MORE---

Display in a destructor: (new) (11-22-2005)
Don't ever try to diplay anything in a class destructor, at least in Windev 5.5... ---MORE---

Focus problem: (new) (11-22-2005)
Building a beautiful and modern UI, with lots of panels/windows interacting with each other can become a nightmare really incredible... ---MORE---

External interaction: (new) (11-22-2005)
And what if it was NOT your code, for once? ---MORE---