> My application would like to send events that I define myself. The problem
> is that I haven't managed to figure out how to use the data section of the
> EventType structure to attach my own data to the event. I figure I can use
> any of the pre-declared structures in the data union, but how do I do if
> none of them suits my needs, i.e. I have other data info. that I would
like
> to attach.
I believe the "data.generic" field is meant for this purpose. It is an
array of eight UInt16's. You'll have to perform type casting or do a
MemMove. I wrote general-purpose C++ templates for this sort of thing:
template <class T>
void Encode(Event &event, const T &t)
{
ASSERT(sizeof(t) <= sizeof(event.data.generic)); // Won't work
otherwise!
MemMove(event.data.generic, &t, sizeof(t));
}
template <class T>
void Decode(const Event &event, T &t)
{
ASSERT(sizeof(t) <= sizeof(event.data.generic));
MemMove(&t, event.data.generic, sizeof(t));
}
And for efficiency I specialized on the UInt16 type (other specializations
are possible):
template <>
void Encode<UInt16>(Event &event, const UInt16 &u)
{
event.data.generic[0] = u;
}
template <>
void Decode<UInt16>(const Event &event, UInt16 &u)
{
u = event.data.generic[0];
}
> Another question is, the PalmOS EvtAddEventToQueue() copies the EventType
> structure passed as parameter. Does EvtAddEventToQueue() perform a mem.
copy
> or does it do an "intelligent" copy based on the event code, i.e. struct
> member by member?
Why wouldn't these be the same?
Eric W. Sirko
Softworks Solutions, LLC
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