Will the critical section work here or should i have to use semaphore or mutex

#include"Derived.h"
int main()
{
	for(int i=0;i<=2;i++)
	{
		Derived *pDerived=new Derived();
		pDerived->fun();
		Sleep(30000);
	}
	return 0;
}

#include <stdlib.h>
#include <stdio.h>
#include <string.h> 
#include <process.h> 
#include<atlstr.h>
#include<Windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
using namespace std; 
class Interface
{
public:
	struct addrinfo    addr_;   
	unsigned short          port_;      
	CString                  hostname_;    
	       
	HANDLE                  threadHandle_;    
	HANDLE                  threadHandle1_;  
	bool                    connected_;     
	SOCKET          sock_; 
	SOCKET ThreadSocket;
	virtual void fun()=0;
	virtual DWORD WINAPI MachineConnectThread(Interface *my)=0;
	virtual int SendRequest(SOCKET sock)=0;      //This will send the request to the machine.
	virtual char* ReceiveResponse(SOCKET sock)=0;  //This will receive the response from the machine that is binary data.
	HANDLE                  threadHandle_;    

};

#include"CBase.h"
class Derived:public Interface
{

public:
	Derived();
	void fun();
	int SendRequest(SOCKET sock);
	char* ReceiveResponse(SOCKET sock );
	 DWORD WINAPI MachineConnectThread(Interface *my);
	static UINT ThreadFunc(LPVOID param) ;
	CRITICAL_SECTION	VarCS;
};

#include"Derived.h"

Derived::Derived()
{

	sock_=INVALID_SOCKET;
	ThreadSocket=INVALID_SOCKET;

		InitializeCriticalSection(&VarCS);

}
void Derived::fun()
{
	printf("in fun function\n");

	//Here socket will be created and will be passed to sebd request and receive response function
	try{
	DWORD dwThreadId;

	threadHandle_=CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)ThreadFunc,this,0,&dwThreadId);
}catch(...)
{
	if(threadHandle_ == NULL)
	{

		printf("Error while creating thread.\n");

		return 0;
	}
}
}
int Derived::SendRequest(SOCKET sock)
{
	printf("in this function request will be sent to server\n");

}
char* Derived::ReceiveResponse(SOCKET sock)
{
	printf("here response wil be received from the server\n");
}
UINT Derived::ThreadFunc(LPVOID param)
{
	Interface* obj = (Interface *)param; 

		obj->MachineConnectThread(obj); // call the member function                       
		// to do the work in our new thread
		return 0;
}
DWORD WINAPI Derived::MachineConnectThread(Interface *my)
{
	ThreadSocket=(SOCKET)my->sock_;
	while(1)
	{
		EnterCriticalSection(&VarCS);//WILL THIS CRITICAL SECTION WORK HERE
		char *buf=NULL;
		char* preBuf=NULL;
		int i=0;
		
		SendRequest(ThreadSocket);
		buf=ReceiveResponse(ThreadSocket);
		Sleep(20000);
		LeaveCriticalSection(&VarCS);
	}
		
		
		
		
			
	
		
		
		
		
				
}