C++ construction weird uninitialized pointer

AlertEvent::AlertEvent(const std::string& text) :
    IMEvent(kIMEventAlert, alertText.c_str()),
    alertText(text)
{
    //inspection at time of crash shows alertText is a valid string
}


IMEvent::IMEvent(long eventID, const char* details)
{
    //during construction, details==0xcccccccc
}

AlertEvent::AlertEvent(const std::string& text) :
    IMEvent(kIMEventAlert, text.c_str()),
    alertText(text)
{
    //inspection at time of crash shows alertText is a valid string
}


IMEvent::IMEvent(long eventID, const char* details)
{
    //during construction, details==0xcccccccc
}