At 7:49 AM -0600 12/15/02, Jeff Wheeler wrote:
>CodeWarrior 8
>Palm OS 5 SDK
>
>I'm working on an app that is written largely in C. I use MemPtrNew() and
>MemHandleNew() and religiously check the return value.
>
>The project uses some shared code, from another developer, that is written
>in C++. So, in the project settings, I have turned on the C++ compiler
>option.
>
>The shared code contains stuff like this:
>
> Char * p = new Char[512];
> if (p == NULL)
> {
> return;
> }
>
>In "Targeting the Palm OS Platform", I read on page 89: "Both new and delete
>throw exceptions that require global variables." This makes me suspect that
>as soon as new and delete are used, I need to also use exception handling.
>However, I haven't been successful at finding other docs that discuss
>exception handling, so I have a few simple questions. Thanks in advance for
>any assistance you can provide.
>
>1. If the "new" allocation above fails, an exception is thrown and the "if
>(p == NULL)" statement is never executed. Is this correct?
Yes.
>2. In the project settings, I have NOT yet selected "enable C++ exceptions".
>Does this prevent "new" from throwing an exception, or merely prevent me
>from catching it?
Don't know - probably the latter, since the exception is thrown from
the library function "new".
>2a. Is there a way to make "new" simply return NULL on failure rather than
>throw an exception?
Yes.
Change the line to
Char * p = new (nothrow) Char[512];
>3. Threads in the archive suggest that CodeWarrior C++ exceptions will do
>stack unwinding. Is this correct?
Yes.
>4. If new throws an exception and it is never caught, what happens? Does
>the app simply exit back to the launcher?
In C++ parlance, an uncaught exception will cause terminate () to be called.
I don't know what that does on PalmOS - certainly it will cause the app to quit.
Back to the launcher is as good a guess as anyones.
>5. What is the proper syntax for catching the exception?
>
> try
> {
> SomeFuncThatMayCallNew();
> }
> catch
> {
> // handle error condition here
> }
Almost:
catch ( <exception type> ) {
>6. Any recommended reading?
Stroustrop's book (get the third edition ).
--
-- Marshall
Marshall Clow Idio Software <mailto:[EMAIL PROTECTED]>
Hey! Who messed with my anti-paranoia shot?
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