UDP数据包传输和C ++

Question

Hello Stackoverflow Community,

I have the following questions when trying to implement UDP transfers using C++:

1) I am trying to build a function that would recieve a simple UDP packet with a string like "/location 7 5" and parse out the float value 7 and 5 out and store it into an array. Are there any examples on how to do this?

2) After trying to use OSCPacket from https://code.google.com/p/oscpack/ for hours, but I cannot get past any compiler errors shown here: http://i.tylian.net/untitloxo.png

As the error message suggests, the error comes from the OSCPack and not my code. Is anyone familiar with this or is there a better method to implement UDP packet transfers?

3) I am only using the ws32.dll library, but are there any other libraries I should be using besides that?

Feel free to respond to some or all of the multipart question and let me know if more detail is needed! Also, my target platform is Windows 7 64-bit.

Thank you very much for your time!

Here are some of the codes I done with OSCPacket:

includes:

#include <iostream>
#include <cstring>

#if defined(__BORLANDC__) // workaround for BCB4 release build intrinsics bug
 namespace std {using ::__strcmp__; }  // avoid error: E2316 '__strcmp__' is not a member of 'std'.
#endif

#include "osc/OscReceivedElements.h"
#include "osc/OscPacketListener.h"
#include "ip/UdpSocket.h"

#define PORT 7000

packet listener

float* coordinateFromOSC = (float*) malloc (2);
class PacketListener : public osc::OscPacketListener {
protected:

    virtual void ProcessMessage( const osc::ReceivedMessage& m, 
                const IpEndpointName& remoteEndpoint )
    {
        (void) remoteEndpoint; // suppress unused parameter warning

        try{
            //the return value, array of 2, [0] for xValue, [1] for yValue
    //will be stored at global variable coordinateFromOSC

    // Trying to parse the packet. osc::OsckPacketListener
            if( strcmp( m.AddressPattern(), "/location" ) == 0 ){
                // Streaming input as argument
                osc::ReceivedMessageArgumentStream args = m.ArgumentStream();
                float xValue, yValue;
                args >> xValue >> yValue >> osc::EndMessage;

            coordinateFromOSC[0] = xValue;
            coordinateFromOSC[1] = yValue;
            }

        }catch( osc::Exception& e ){
            // any parsing errors such as unexpected argument types, or 
            // missing arguments get thrown as exceptions.
            std::cout << "Invalid format: "
                << m.AddressPattern() << ": " << e.what() << "\n";
        }
    }
};

and lastly in the function where I need the stored values

PacketListener listener;
UdpListeningReceiveSocket s(IpEndpointName( IpEndpointName::ANY_ADDRESS, PORT ), &listener );

Answer 1

If you continue to have issues with your current library, you might want to take a look at Boost and the ASIO library.

This page UDP Echo Server Example might help you get started.

Answer 2

To parse strings in C++, try the stream operators (aside: does your input actually need to be strings?):

std::string str("/location 7 5");
std::stringstream ss(str);
std::string cmd;
float x, y;
ss >> cmd >> x >> y;

For OSCPacket, it's possible that you have not set up the project settings properly. Why not just use Winsock?

For an example of using Winsock, see http://www.adp-gmbh.ch/win/misc/sockets.html