Why console app hangs when using a shared dll that containg static variable that use mutex? - multithreading

Question

I have a shared dll library that contains a class as below :
inside A.dll >> Header File :
class API ErrorHandler
{
public:
ErrorHandler();
virtual ~ErrorHandler();
protected:
static ErrorHandler* defaultHandler();
private:
static ErrorHandler* _pHandler;
static std::mutex _mutex;
};
source(.cpp)
ErrorHandler* ErrorHandler::_pHandler = ErrorHandler::defaultHandler();
std::mutex ErrorHandler::_mutex;
ErrorHandler::ErrorHandler()
{
}
ErrorHandler::~ErrorHandler()
{
}
ErrorHandler* ErrorHandler::defaultHandler()
{
static SingletonHolder<ErrorHandler> sh;
return sh.get(); **<<====== here we get hanged** see the declaration of get
}
SingletoneHolder header file
template <class S>
class SingletonHolder
{
public:
SingletonHolder():
_pS(0)
{
}
~SingletonHolder()
{
delete _pS;
}
S* get()
{
std::lock_guard<std::mutex> lock(_m); <===== cause thread hang
if (!_pS) _pS = new S;
return _pS;
}
private:
S* _pS;
std::mutex _m;
};
After building the above code (every thing related to compiler setting configured correctly) now I want to use it in my console app.
After running console app, app hangs and never reach to main function.
Why std::lock_guard<std::mutex> lock(_m); hangs and prevent main thread to continue executing?
What is alternative?
I am using VS2013 Update5.
content of main file :
#include "ErrorHandler" <== when remove this include app run correctly
#include <iostream>
int main()
{
getchar();
return 0;
}

Answer 1

First, you should post exact contents of the main - with an empty main everything works. Things go south when the ErrorHandler class is being instantiated inside main.
Second, the initialization of your static members occurs inside __DllMainCRTStartup and as stated in the SO question I marked as duplicate, MSDN states that using synchronization primitives from __DllMainCRTStartup can cause a deadlock. A possible solution is to switch to a critical secion.