Heap corruption detected in class (after delete) but is only triggered when used within a dll, not an exe

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4.50/5 (2 votes)

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I have a class that I use for socket communications (old code, not written by me) that I'm attempting to clean up, when I do this (for testing purposes):

C++

CCommSocket *tst = new CCommSocket;
delete tst;

I get a heap corruption debug error when the code is used in a dll, since I couldn't see anything that could cause that within the class, I took the class and placed it within the main exe and it news/deletes with no problem. I'm guessing this has something to do with the class being in the dll. Anyone have any idea what would cause a heap corruption problem such as this within a dll and not an exe?

...and yes, the calls are right next to one another (for now), both within the dll...

--Update--
The base class for CCommSocket had a bool that I recast to BOOL and now it works fine. Doesn't really make sense, specially because there's another bool in the class as well. :doh:

--SOLVED--
http://www.codeproject.com/Messages/3797525/Re-class-size-doesnt-seem-to-be-determined-correct.aspx[^]

Posted 3-Mar-11 13:02pm

Albert Holguin

Updated 5-Mar-11 11:35am

v6

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2 solutions

Solution 1

It seems to be using MFC as part of a DLL issue. You may need to check following links.

http://msdn.microsoft.com/en-us/library/zfz4xb9a.aspx[^]

http://msdn.microsoft.com/en-us/library/hw85e4bb.aspx[^]

Posted 4-Mar-11 13:29pm

Ozer Karaagac

Comments

Dalek Dave 4-Mar-11 19:33pm

Good Links.

Albert Holguin 4-Mar-11 23:05pm

Yeah nice links but really have nothing to do with my question... the code seems to work just can't delete properly, creating a memory leak.

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Ozer Karaagac · Accepted Answer · 2011-03-05T11:27:00

Solution 2

Is there any #pragma pack(#) or __declspec(align(#)) directive somewhere (may affect it) before your class?

If the base class' implementation is in pre-compiled form or it is an MFC class while using MFC in shared libs, default packing alingment is 4 (for x86). As you may know, BOOL is defined as type "int" which is 4 bytes in size while bool is 1 byte.

Posted 5-Mar-11 11:27am

Ozer Karaagac

Comments

Albert Holguin 5-Mar-11 17:33pm

A few more details if anyone's interested (thanks to ozer for helping) are included in a link in the main question.