Is it possible to tell if WSAStartup has been called in a process?

Yes it is possible.

And here is how it's done.

bool WinsockInitialized()
{
    SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (s == INVALID_SOCKET){
        return false;
    }

    closesocket(s);
    return true;
}

int main()
{
    //...
    if ( !WinsockInitialized() )
       // Init winsock here...

    // Carry on as normal.
    // ...         
}

But it's not really necessary to do this. It's quite safe to call WSAStartup at any time. It's also safe to end each successful call to WSAStartup() with a matching call to WSACleanup().

e.g.

// socket calls here would be an error, not initialized
WSAStartup(...)
// socket calls here OK

WSAStartup(...)
// more socket calls OK

WSACleanup()
// socket calls OK

WSACleanup()

// more socket calls error, not initialized

• No, it is not possible to tell if WSAStartup() has already been called.

• Yes, WSAStartup() can be called multiple times in a single process, as long as the requested version is supported by the WinSock DLL. Calls to WSAStartup() and WSACleanup() must be balanced.

• WinSock initialization is a negotiated process; you are responsible for validating the info that WSAStartup() returns to make sure it meets your app's requirements.

• Existing sockets are not affected by subsequent WSAStartup() calls.

• Multiple sockets using different WinSock versions is allowed.

See the WSAStartup() documentation for more information.