bool QSerialPort::waitForReadyRead(int msecs)
{
#ifdef USE_POSIX_SYSCALLS
    struct timeval tv;
    fd_set readSet;
    if ( d->fd != -1 ) {
        tv.tv_sec = msecs / 1000;
        tv.tv_usec = msecs * 1000;
        FD_ZERO( &readSet );
        FD_SET( d->fd, &readSet );
        return ( select( d->fd + 1, &readSet, 0, 0, &tv ) > 0 );
    } else {
        return false;
    }
#else
    return false;
#endif
}

/*!
    \reimp
*/
qint64 QSerialPort::bytesAvailable() const
{
#ifdef USE_POSIX_SYSCALLS
    if ( d->fd != -1 ) {
        // See comments in Qt4's qsocketlayer_unix.cpp for the reason
        // why this ioctl call sequence is a little bizarre in structure.
        size_t nbytes = 0;
        qint64 available = 0;
        if (::ioctl( d->fd, FIONREAD, (char *) &nbytes ) >= 0)
            available = (qint64) *((int *) &nbytes);
        return available;
    } else {
        return 0;
    }
#else
    return 0;
#endif
}

/*!
    \reimp
*/
qint64 QSerialPort::readData( char *data, qint64 maxlen )
{
#ifdef USE_POSIX_SYSCALLS
    int result;
    if ( d->fd == -1 ) {
        return -1;
    }

    while ( ( result = ::read( d->fd, data, (int)maxlen ) ) < 0 ) {
        if ( errno != EINTR ) {
            if ( errno == EWOULDBLOCK ) {
                return 0;
            }
            qLog(Modem) << "read errno = " << errno;
            return -1;
        }
    }

    if ( !result && ( !d->isTty || ( !d->keepOpen && !dsr() ) ) ) {
        // We've received a close notification.  This might happen
        // with the phone simulator if it is shut down before Qtopia.
        // Don't do this for tty devices because there are some systems
        // that return zero when they should be returning EWOULDBLOCK.
        qLog(Modem) << "QSerialPort::readData: other end closed the connection" ;
        close();
    }
    //data[strlen(data)-1]=0x0;
    return result;
    //return result;
#else
    return -1;
#endif
}