Thread: error with function

Hi,

I am trying to write a function but keep getting an error when I try to build. I'm not very experienced with c++ so I can't really figure out what the error means. The funcion is called like this:

Code:

nMarkerCount = netClient.GetMarkerCount();

and it looks like this:

Code:

int BMLClient::GetMarkerCount(void)
{
	if (!m_bConnected) return 0; //??

	long cmd = 3;
	if (!Send(&cmd, sizeof(cmd)))
	{
		std::cout << "Unable to send <get marker data> command" << std::endl;
		return false;
	}
	long count;
	if (!Recv(&count,sizeof(count)))
	{
		std::cout << "Unable to get marker count" << std::endl;
		return false;
	}
	m_nMarkerCount = count;
	m_buffer = new double[count*3];
	m_bConnected = true;
	return m_nMarkerCount;
}

I have declared it as public in the header file like this:

Code:

int GetMarkerCount(void);

The error that I get says: error C2662: 'BMLClient::GetMarkerCount' : cannot convert 'this' pointer from 'const BMLClient' to 'BMLClient &'


Can anyone tell from what I've posted what this error means? Thanks!

This probably isn't causeing that error but I can see two places where you're returning a bool instead of an int.

netClient is declared as:

Code:

protected:
	BMLClient netClient;

in this class:

Code:

class BMLDrawable: public osg::Drawable

i'm not sure what you mean by the class definition code....what else do i need to post?

ok hopefully this is the one

Code:

#pragma once
#include <winsock2.h>
#include "Vector3.h"

class BMLClient
{
public:
	BMLClient(void);
	virtual ~BMLClient(void);

	bool Connect(void);
	void Disconnect(void);
	bool isConnected(void) const { return m_bConnected; }
	int GetMarkerCount(void);
	void GetFrame(CVector3* buf) const;

protected:
	bool m_bConnected;				// true when connection to server established successfully
	int m_nMarkerCount;				// number of targets being tracked
	SOCKET m_socket;				// network socket connection to BML server
	double *m_buffer;				// buffer for frame data

	bool Send(void* buf, long size) const;
	bool Recv(void* buf, long size) const;
};

>> nMarkerCount = netClient.GetMarkerCount();

The place that the function call above is made is probably inside a BMLDrawable member function, right? If so, then is that member function const? Show the declaration of the function that contains the line above.

yup it's a const....here it is:

Code:

void BMLDrawable::drawImplementation (osg::State& state) const
{
	if (!netClient.isConnected()) return;

	nMarkerCount = netClient.GetMarkerCount();

	// draw a sphere at each joint
	glColor3fv(red);
	glEnable(GL_LIGHTING);
	for (int m=0; m<nMarkerCount; m++)
		GenSphere(frameData[m],BALL_RADIUS);
	
	// get next batch of frame data
	netClient.GetFrame(frameData);
}

ok maybe this is stupid but i'm still not really sure how to fix this

hmmm yea that's the first thing i tried but it's giving me more errors in this class:

Code:

class BMLDrawable: public osg::Drawable {
public:
	BMLDrawable();
	virtual ~BMLDrawable();

	virtual osg::Object* cloneType() const
	{
		return new BMLDrawable();
	}

	virtual osg::Object* clone(const osg::CopyOp&) const
	{
		return new BMLDrawable();
	}

	bool computeBound() const;
	virtual void drawImplementation(osg::State& state);

protected:
	BMLClient netClient;
	CVector3 *frameData;
	int nMarkerCount;
	GLuint nSphere;
	void GenSphere (CVector3 &center, GLfloat radius) const;
};

the errors say "error C2259: 'BMLDrawable' : cannot instantiate abstract class"

any clue what that means?

i'm not really sure what a pure virtual function is...how would i know?