Multi-threaded environment, other threads never get access to critical section

Question

Right now I am stuck, here is what I'm trying to do:

Create 3 threads:
These 3 threads will access a shared global resource (a vector)

At a certain point in the function (that all threads will call), there will be a Sleep(time) function, which makes the thread sleep, the function does not return. This is where I want another thread - thread 2, to access and use the function, modifying the global variable, until it sleeps, so thread 3 can access the function, ect...

The "critical section" function which accesses the global variable has an unspecified access time, it is never the same.

Initially, in main I call

    InitializeCriticalSection(&m_stCriticalSection);

What I attempted was, when this function is called, I immediately call

EnterCriticalSection(&m_stCriticalSection);

I then modify global variables, ect, then before the Sleep(time) I call

        LeaveCriticalSection(&m_stCriticalSection);

Problem with this is, the other threads don't EVER get access to the function, even though I leave it. Is there a way for my other threads to continuously, or even every 5 seconds, get access to the critical section? Could my implementation be better?

So here's what I have now

void function() // all our threads will access this
{
   EnterCriticalSection(&obj)
   // manipulate global data
   LeaveCriticalSection(&obj)
   Sleep(long time) // another thread SHOULD NOW have access to this section!
   return true;
}

yuriy206 yuriy206 · Accepted Answer · 2013-06-09T01:24:43

Is there any possibility that a process is failing in the "// manipulate global data" section?

If so, then LeaveCriticalSection(&obj) would never be called.

Have you tried putting debug logs right before LeaveCriticalSection(&obj)?

Multi-threaded environment, other threads never get access to critical section

2 Answers