Joe,
One way to set all bytes of a structure to zero is to use
MemSet (void *changeThis, UInt32 numberOfBytes, Byte value)
(reference "Palm OS Programming Bible 2nd Edition", Lonnon R. Foster)
as in
struct xStruct { ... };
MemSet (&xStruct, sizeof(xStruct), 0);
Al
----- Original Message -----
From: "Keith Rollin" <[EMAIL PROTECTED]>
To: "Palm Developer Forum" <[EMAIL PROTECTED]>
Sent: Saturday, March 27, 2004 9:45 PM
Subject: RE: Structure initialisation
Joe,
This is a generic C programming question. It is not specific to Palm OS or
its development tools, so you should probably post questions like this in a
"how to program in C" forum.
In short, static structs (that is, those created as global variables or as
statics local to a function) have their fields initialized to zero when the
application starts. Automatic structs (that is, those created as local
variables) or structs allocated with malloc or MemPtrNew will have garbage
in their fields. It is up to you to initialize them to appropriate values
after you've allocated the memory for them.
There is no supported method for determining if a pointer type contains a
valid or invalid value.
-- Keith
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of joe
bloggs
Sent: Saturday, March 27, 2004 6:37 PM
To: Palm Developer Forum
Subject: Structure initialisation
Hello Forum,
When a structure is created, does anyone know if it's
elements are initialised? e.g. initegers set to 0 and
pointers/references set to NULL.
The reason I am asking is that my error handling code
deallocates memory by checking if mem pointers are not
NULL. If structure elements are initialised, I can
check to see if memory has been allocated as follows:
if (someStruct.memPointer)
...
If structure elements are not initialised, can anyone
recommend a way to determine if a pointer is pointing
to allocated memory (instead of just garbage).
--
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