Please bear with me while I attempt to explain my problem. I am having a
bit of trouble from a conceptual angle with saving and retrieving data. So
you all know, I have looked through the source of the ROM applications and
have searched the knowledge base and list archive. Many sources address my
question but there is always some small part missing, so please take a look
and let me know what your thoughts are.
I begin with a structure of Char* that relate to different fields on a form
(Name, Address, Phone Num, etc).
typedef struct {
Char* Name;
Char* Address;
Char* Company;
...
} MeetingType;
Now, to fill this structure with the relevant data, I have a save routine
that is registered as a callback function for a table. This save routine
gets a handle to the current field, locks this handle and assigns the
returned pointer to the members of the structure.
field = TblGetCurrentField(table);
fieldH = FldGetTextHandle(field);
...
cRecord.Name = MemHandleLock(fieldH);
This is where it gets a bit fuzzy for me. I can't unlock that handle
because the pointer I just assigned to cRecord.Name may become invalid if
the OS decides to change it. But I don't think I should leave it locked
either. Also, this can't be the correct way to do this because after I save
this to the database by passing the structure to DmWrite and restart the
application, the address that I assigned to cRecord.Name shouldn't be valid
anymore as dynamic memory will have been reset. As evidence of this, the
above code works while the application is running but the moment I exit the
application and restart it I receive errors when trying to reference
cRecord->Name (The error is: "Meeting" 1.0 has just read directly from an
unallocated chunk of memory).
I guess my question comes down to what datatype should use in my structure?
Should I use pointers at all for the data I store using the data manager?
If not, what do I use? If so, how exactly does that work? One only has
direct access to dynamic memory which will be invalid after an application
exits.
I would greatly appreciate some direction here. Thank you in advance.
Justin Felker
[EMAIL PROTECTED]
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