Method IsReadDataAvailable

Core/ConnectionSML/src/sock_Socket.cpp:273–335

//////////////////////////////////////////////////////////////// Function name : Socket::IsReadDataAvailable Argument : int secondsWait -- Seconds part of how long to wait for data in secs (0 is default) Argument : int millisecondssecondsWait -- Milliseconds part of how long to wait for data in usecs (0 is default, must be < 1000) Return type : bool Description : Returns true

//
/////////////////////////////////////////////////////////////////////
bool Socket::IsReadDataAvailable(int secondsWait, int millisecondsWait)
{
    assert(millisecondsWait < 1000 && "specified milliseconds must be less than 1000");
    
    CTDEBUG_ENTER_METHOD("Socket::IsReadDataAvailable");
    
    SOCKET hSock = m_hSocket ;
    
    if (!hSock)
    {
        if (m_bTraceCommunications)
        {
            sml::PrintDebug("Error: Can't check for read data because this socket is closed") ;
        }
        return false;
    }
    
    fd_set set ;
    FD_ZERO(&set) ;
    
    //////
    // This _MSC_VER test is legit, for a warning C4127: conditional expression is constant in a
    // windows-defined FD_SET macro below
#ifdef _MSC_VER
#pragma warning(push, 3)
#endif
    // Add hSock to the set of descriptors to check
    // This generates a warning on level 4 in VC++ 2005.
    FD_SET(hSock, &set) ;
#ifdef _MSC_VER
#pragma warning(pop)
#endif
    //////
    
    // Wait for milliseconds for select to return (can be 0 to just poll)
    TIMEVAL zero ;
    zero.tv_sec = secondsWait ;
    zero.tv_usec = millisecondsWait * 1000 ;
    
    // Check if anything is waiting to be read
    int res = select(static_cast<int>(hSock) + 1, &set, NULL, NULL, &zero) ;
    
    // Did an error occur?
    if (res == SOCKET_ERROR)
    {
        if (m_bTraceCommunications)
        {
            sml::PrintDebug("Error: Error checking if data is available to be read") ;
        }
        sml::ReportSystemErrorMessage() ;
        Close() ;   // If the socket has an error we'll shut it down
        return false ;
    }
    
    bool bIsSet = FD_ISSET(hSock, &set) ? true : false ;
    /*
        if (bIsSet)
            sml::PrintDebug("Read data IS available") ;