BorlandTalk.com

Ashley Berlin · Guest

I've been using TReader and TWriter to write a collection to a file -
i'm using it to store settings.

I have ben constantly getting a code guard error whenever i create a reader

TReader* Reader = new TReader(fs, 4096);
// fs i an opened TFileStream

I get the following code guard error:

Method called on illegally casted object:
Attempt to access 128 byte(s) at 0x0412B228. The 'this' pointer points
to heap block 0x0412B228 which is only 124 bytes long.

I was horrified to discover that

int sz = sizeof(TReader) - InstanceSize(__classid(TReader));

returns a value of 4 - i.e. sizeof(TReader) is four bytes larger than it
should be! I have found a solution to this, but i dont like it:

In Classes.hpp i placed #pragma pack(4) .. #pragma pack() directives
around the definition of TReader and TWriter (same problem). How much
of a bad idea is this?

The other problem I have been having is that it does not read the count
properly: Collection->Count always says 1, however
Collection->FItems->Count returns the correct value? Any clues to
solving this one?

Thanks in advance
Ash Berlin

Maynard Philbrook · Guest

that is not correct.
use the size(Reader) instead..
it will return the size of the instance which is 4 bytes.
what your getting is the size of the Class it self and is not valid for what
your doing.
InstanceSize is the actual size of the allocated chuck of memory new creates
for the
class.
the class code is different from the instance code when using Pointer types
/Dynamic types.
ect..

Ashley Berlin wrote:

Fishface · Guest

Ashley Berlin wrote: