[Quickfix-developers] 1.2.1 ThreadedSocketAcceptor synchronization suggestion

[Gene G. <mus...@ya...>]

I am looking at the ThreadedSocketAcceptor class, and
I have noticed that although onStop will likely to run
while onStart is looping, the access to m_stop is not
guarded. 

One way to quick fix this (ha) to use an mt_var class
:
//T must be copyable 
template<class T>
class mt_var {  
public:
  mt_var(const T &out) : m_val(x) {}

  void operator= (const T &in) { locker lock(m_mutex);
m_val = in; }
  operator T () { locker lock(m_mutex); return m_val;
}

protected:
  mutex m_mutex;
  T m_val;
};

In that case the only change required in the code in
question would be change
bool m_stop; 
to 
mt_var<bool> m_stop; 


Of course shutting down m_socket while accepting in
another thread is also prone to race conditions, but
in the OS that I use Quickfix (Win/Linux) the code
works OK.

I usually prefer a portable solution by locally
connecting to the socket and sending a shutdown
message. Of course one could also use non-blocking
poll/select with timeout.

Gene Gorokhovsky




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