Re: EnterCriticalSection() is corrupting my heap

From:

"Doug Harrison [MVP]" <dsh@mvps.org>

Newsgroups:

microsoft.public.dotnet.languages.vc,microsoft.public.vc.debugger,microsoft.public.vc.language

Date:

Wed, 24 May 2006 23:07:47 -0500

Message-ID:

<kuaa729e27jt968cpek8oqom49ak0p5nhk@4ax.com>

On Wed, 24 May 2006 15:19:27 +0200, "Arsalan Ahmad" <arsal__@hotmail.com>
wrote:

Hi,

Yes i use HeapCreate() and HeapAlloc().

I have a class object which is created on the heap and I have a member
variable in this class of type CRITICALSECTION (say m_cs). Inside one of my
class function when I call EnterCriticalSection(&m_cs) then this problem
occurs. Ok may be its not because of critical section because at the place
in code where EnterCriticalSection() was being called I create and
CAutoLock() object and pass my pointer to CRITICALSECTION object to it
(CAutoLock just call EnterCriticalSection in its constructor and
LeaveCriticalSection in its destructor). In the constructor when I try to
save pointer of critical section to the class member (CRITICALSECTION
*m_pCS) of CAutoLock then although it is pointer assignment but after
assignement the class member has some garbage data.

In my outside code:

{
   CAutoLock(&m_cs);

   // Some code
}

CAutoLock::CAutoLock(CRITICALSECTION *pCS)
{
   m_pCS = pCS; <= This assignement is not working correctly and after
assignment m_pCS points to some garbage memory location
   EnterCriticalSection(m_pCS);
}

So any idea what is wrong?

I see you corrected the above in a subsequent message, but it's worth
mentioning that the following will indeed compile, but it won't do what you
want:

{
CAutoLock(&m_cs);

// Some code
}

This will just create a temporary CAutoLock object and immediately destroy
it, so the code which follows it in the block will not execute in a
critical section.

--
Doug Harrison
Visual C++ MVP