Re: can I share a variable between two threads?
"Tom Serface" <tom.nospam@camaswood.com> wrote in message
news:E6D58585-918F-4312-B959-F87585981BD6@microsoft.com...
In addtion to what Scott and David wrote... I've found that having the
thread own the data and then setting flags that indicate to a thread loop
that things need to be changed works well. It doesn't preclude the need
for the CriticalSection() necessarily, but, for example, I would only
allow my thread loop to add or delete values from the queue.
Hmm, it would seem putting write access in the thread loop makes synchronous
write/read access impossible. The caller cannot wait for the write to occur
before proceeding.
I find the easiest way to make MFC collections thread safe is to derive a
class such as
class CSafeMapStringToString : CMapStringToString
{
public:
AddItem (const CString &strKey, const CString &strValue);
RemoveItem (const CString &strKey);
CString LookupItem (const CString &strKey);
protected:
// all other members are protected, not accessible to caller
};
And the 3 public methods use a critical section to ensure synchronization.
That way the caller doesn't need to do anything to ensure thread safety,
which really keeps the caller code clean. I dislike code litered with all
manner of critical section usage, since it gets in the way of clearly
illustrating the purpose of the code with implementation details. Come to
think of it, that's why I hate COM and love .NET so much.
-- David