> Anyway, confession time! I'm actually allocating my own stack prior to calling
TimSetSeconds.
> If I don't then I actually get the stack overflow error at some point later
via gremlins.
I still don't know which error you're getting, but I think that TimSetSeconds
(in PalmOS3.5) actually broadcasts a _deferred_ notification. This means the
notification isn't broadcast (and thus, the stack isn't checked) until the next
time you call EvtGetEvent().
> Unfortunately PalmOS isn't very good about guaranteeing
> stack space to notification handlers. In fact, it doesn't
> do anything about this at all.
Actually, this is not true. I missed the original message that started this
thread (sorry), but if the NotifyMgr is giving you trouble because of
lack-of-stack space (what sort of trouble were you having, precisely?) then its
probably because it DOES (attempt) to do something about this. In some places
PalmOS takes a bit of a lazy attitude towards stack space issues, and it causes
trouble now and again. But the NotifyMgr is at least a bit better about it...
Before a notification handler is called (either a callback function or PilotMain
via SysAppLaunch) NotifyMgr makes sure there are at least 256 bytes of stack
available. Or at least, thats the theory, and the API test guys said that it
was working. One of the possible problems here is that I have no idea how much
stack space is used by SysAppLaunch (if you're not using callback procedures for
notification), and this comes out of the 256 bytes that are reserved for your
handler. Also, if your handler calls OS routines that use a lot of stack space,
then maybe 256 bytes isn't enough.
> Well, allocating your own stack would explain a lot. If the stack pointer is
in
> this seperate block, then it's outside the range returned by SysStackInfo.
This is a really good point (thanks, Keith!!).
The code in PrvCheckStackSpace() looks at the range returned by SysStackInfo(),
and compares it to the current stack pointer. If the SP is within 256 bytes of
the end, it returns sysNotifyErrNoStackSpace. If the SP has overflowed the end
of the stack, then you get a fatal error. So, when you allocate your own stack,
it will either be before or after the "official" stack chunk, and either way its
outside of the 'official' stack range. One way, it will look as if you've got
LOTS of stack space left (when you might not, really), and the other way it will
look as if you've _really_ overflowed your stack (hence you get the fatal error
when maybe you shouldn't). So, you're either bypassing the NotifyMgr's error
checking, or you are rendering it useless ('cause it won't broadcast anything).
Does this clear things up a bit?
Jesse
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