CMap, CList, CArray Thread safe?

Victor Silva

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Jan 22, 1997, 3:00:00 AM1/22/97

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Are the MFC CArray, CMap and CList classes thread safe (i.e. must I
implement a mutex area when one thread adds to a CMap and
another thread removes from the same CMap?)

Thanks,
Vic

Todd Whitmore

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Jan 22, 1997, 3:00:00 AM1/22/97

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Victor Silva <inv...@email.address> wrote in article
<01bc0889$6b163310$bc941ace@silv>...

> Are the MFC CArray, CMap and CList classes thread safe (i.e. must I
> implement a mutex area when one thread adds to a CMap and
> another thread removes from the same CMap?)

They are not thread-safe. Gate access to the data structures using a mutex
semaphore, or better yet - derive a class from CMap etc and hide the mutex
code with your class

Dave Steckler

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Jan 22, 1997, 3:00:00 AM1/22/97

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No, they are not threadsafe. You can checkout \msdev\mfc\include\afxtempl.h
yourself on issues like this, btw. :-)

Victor Silva <inv...@email.address> wrote in article
<01bc0889$6b163310$bc941ace@silv>...
> Are the MFC CArray, CMap and CList classes thread safe (i.e. must I
> implement a mutex area when one thread adds to a CMap and
> another thread removes from the same CMap?)
>

> Thanks,
> Vic
>

Regis NICOLAS

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Jan 23, 1997, 3:00:00 AM1/23/97

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Victor Silva <inv...@email.address> wrote in article
<01bc0889$6b163310$bc941ace@silv>...
> Are the MFC CArray, CMap and CList classes thread safe (i.e. must I
> implement a mutex area when one thread adds to a CMap and
> another thread removes from the same CMap?)
>
> Thanks,
> Vic
>

To keep MFC classes efficient their designers have decided not to
thread-protect them at the object level but at the class level. It's a very
good choice. If YOU want to use a map, YOU must synchronize accesses. For
that you can either use a CSingleLock Object or a Critical Section. They
are lightweight. A Mutex or a Semaphore is rather hammer-like objects for
your case.
I don't recommend to subclass a CArray for bug and performance reasons...
If you really want to encapsulate the lock use aggregation rather. Create a
new CMyArray that contain a ptr to a CArray...

Hope it helps

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