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Re: C++ class member alignment in Xcode

It's funny that you should ask this. I just finished chasing down the very same kind of problem in our project earlier in the week.

There are two #pragmas that can change your struct alignment: "#pragma options align" or "#pragma pack". These are usually used in pairs so the packing is changed for known data structures. In our case, we were using "#pragma options align=..." and forgot to close it with "#pragma options align=reset" in a header file. Since this malformed header was included in many places, it had side-effects in each file that used it.

The compiler never complained, but I had a situation where sizeof ( myClass ) would return different sizes in different .cpp files.

So, I would be looking for #pragmas and making sure they were all closed properly.

	-Wyatt

On Feb 8, 2007, at 11:05 AM, <email@hidden> <email@hidden> wrote:


Hello,

I am having a problem with a derived class accessing members in the base
class. It looks like this:


[...]


I have preformed a clean rebuild of the project and get the same result.
Why does one file use 4-byte alignment while another on in the same
project uses 2-byte?

Regards,

Ron Lingl
Interactive Solutions, Inc.


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