What's the difference between char * and const_cast<char*>(string.c_str())

I use an external library to deal with udp (OSC) communication between 2 apps. To format the messages that will be sent, the library is expecting a char* but I get a string from the UI that I have to convert. While I was dealing with other parts of my code the udp part was hard coded like that : ``` char* endofMess = "from setEndMess"; ``` and was working fine. I thought it would be easy to get it working with my strings and wrote : ``` std::string s = "from setEndMess"; char* endofMess = const_cast<char*>(s.c_str()); ``` but unlike for the first example where I was receiving the message correctly formatted, I now receive only gibberish characters. Does somebody know where it can come from? Thanks! Matthieu EDIT : the code I use : The method to send the message each time OSCVal will change : ``` void osc500::testOSC(int identifier, float OSCval) { UdpTransmitSocket transmitSocket( IpEndpointName( destIP, port ) ); char buffer[1024]; osc::OutboundPacketStream p( buffer, 1024 ); p << osc::BeginBundleImmediate << osc::BeginMessage( endofMess ) << OSCval << osc::EndMessage << osc::EndBundle; transmitSocket.Send( p.Data(), p.Size() ); } ``` And if I have to change the OSC pattern I call this one : ``` void osc500::setEndMess(String endpattern){ // endofMess = "from setEndMess"; //OK works fine each time it's called //1st try : //std::string s = "from setEndMess"; //endofMess = const_cast<char*>(s.c_str()); //gibberish //2nd try : //std::string s = "from setEndMess"; //endofMess = &s[0]; //gibberish //3rd & 4th tries : //char s[4] = {'t','e','s','t'}; //char s[5] = {'t','e','s','t','\0'}; //endofMess = s; //gibberish } ```