> From: Vitaly_Romanishko
>
> How can we support PalmOS 3.5 and 3.1 at the same time if:
>
> 1. When you creating a new project in CodeWarrior you have to choose
> between following
> a. Palm OS 3.1(English) Stationary
> b. Palm OS 3.5 Stationary
> Hence CodeWarrior will generate machine code targeting
> either 3.5 or 3.1 version, but not both!
>
This is a common misunderstanding that some new Palm OS developers have.
You should pick "Palm OS 3.5 Stationery" for your project. You can write a
single application that runs unmodified on all versions of the OS. With
each new version of the SDK, Palm adds new functions for new features. In a
few rare cases, there is more than one version of a single function, with
different names, and your app has to test for the OS version before deciding
which to use. Most often, you just decide which version will be the
"minimum" your app should run on and then only use functions that existed in
that version (or earlier). For example, you can call FrmSetMenu if your app
is running under Palm OS 2.0 (or later), you can call WinDrawChar if your
app is running under Palm OS 3.1 (or later), etc.
See the Compatibility Guide of the SDK Reference to learn about this.
> 2. Beside different compiler setting Palm OS 3.5 handling forms
> differently. If you use standard
> code to handle forms it will crash 3.5 debug rom. At the
> same time if you target Palm OS 3.5 -
> prior versions will not function properly.
>
This is not true.
> 3. Palm OS 3.5 handle writing on the screen different than 3.1. If you
> use standard approach which works for versions
> 3.0-3.3 you will crash 3.5 debug ROM.
>
Normally, you should not be writing directly to the screen. However, if you
must do so, then see Aaron Ardiri's sample code to learn how to do it.
(There were posts about this just today, so see the archives, too.)
> 4. Palm OS 3.5 using improved functionality for Bitmaps. But these new
> functions are not recognized
> by versions 3.1-3.3, they simply crash. If you use old
> approach to bitmaps it gives errors in Palm 3.5.
>
See explanation of point #1. The new functions didn't exist in the old
versions of the OS.
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