Regarding Synchronization Objects.

[Fandu_Nagesh]

Hi
I am writing one multi-threaded application. I need to synchronize the threads for data sharing.
But I am not getting which is suitable to use. I mean Mutex/CriticalSection or Semaphore.

I will be grateful if you provide me the details advantage and disadvantages of these.

Regards,
Nagesh

[Siddhartha]

I think the Thread mentioned below should give you some information you need + links to FAQs.
Threads in Visual C++ (http://www.codeguru.com/forum/showthread.php?t=334454)

A useful link from MSDN...
Synchronization (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/synchronization.asp) :thumb:

[Fandu_Nagesh]

Hi,

Thanks for such informative article.

Regards,
Nagesh

[Siddhartha]

Thanks for such informative article.
You are welcome.

Ciao,
Sid!

[BOswalt]

If you are doing a multithreaded application and locks across processes aren't necessary, then you almost always want to use a critical section.

The best way to do this, in my opinion, is to use the raw Win32 objects themselves, like this:

Class member or persistent member variable:

CRITICALSECTION m_cs;

Constructor or Init routine:

InitializeCriticalSection(&m_cs);

Destructor or Cleanup routine

DeleteCriticalSection(&m_cs);


Then, use a separate class like this:

CMyLock::CMyLock(LPCRITICAL_SECTION pCs) {
m_pCs = pCs;
EnterCriticalSection(pCs);
}

CMyLock::~CMyLock() {
LeaveCriticalSection(m_pCs);
}

Then, when you have a section that needs to be thread safe, you should lock like this:

void CMyClass::Function() {

// This section needs a critical section
{
CMyLock lock(&m_cs);
// Do my thread safe stuff
}


}

In this way, C++ scope rules take care of the locking/unlocking for you, and you can reduce your deadlock probability.