I'm trying to use a CCriticalSection, but failing. I get access violations
when I try to lock. So I'm clearly doing it wrong.
Here's the scenario:
Class A creates a worker thread.
Class A wants to queue up items for the worker thread to handle one at a
time. These items can be represented by a single UINT.
Thus, I believe I am correct in saying that I should be using a critical
section to control putting things into the queue and pulling things out of
the queue, so they don't clash. (Clearly I've never used a sync object
before).
For now, I was trying to use a CUIntArray as the queue itself (probably not
the most efficient, but I just want to get it working first before I worry
about efficiency - but I'm open to better suggestions of MFC (not ATL,
sorry) objects to use for a queue).
But, this array is a member of a structure declared globally:
(Header file)
typedef struct tagItemQueue
{
BOOL bTerminate ;
CUIntArray aryItems ;
} ITEM_QUEUE ;
(Implementation file)
static const g_sItemQueue ;
This is passed (by its pointer) as the user parameter to the worker thread
on creation (I could use the global reference, but chose not to). The worker
thread then tries to access it.
This all seems to work fine.
So now I tried adding a critical section, by updating the structure:
typedef struct tagXXX
{
BOOL bTerminate ;
CUIntArray aryItems ;
CCriticalSection CriticalSection ;
} XXX ;
Accordingly, in the thread (and where it tries to add things to the queue),
I try:
if (psQueue->CriticalSection.Lock(1000) )
{
// Do something thread-safely...
psQueue->Unlock();
}
But when I run the program, it access violates at the .Lock() line.
Have I done something wrong? This is the best I can make out from MSDN on
CCriticalSection (I tried using a CSingleLock in conjunction with it, but
that failed too, although for different reasons that I can't fathom - so I
used the critical section directly, as MSDN says I can).
--
Jason Teagle
[EMAIL PROTECTED]
