// outside your class ...
const HANDLE MultiReader::hReaderMutex = CreateMutex( NULL, TRUE, "ReaderMutex");

// MultiReader.h
class MultiReader :
	public DirectoryReader
{
public:
	MultiReader(char* p_sConfigPath);
	~MultiReader(void);
 
	static const HANDLE hReaderSemaphore;
	void CreateThreads(void);
	static DWORD WINAPI ReaderThread(PVOID p_pVoid);
};

// MultiReader.cpp
 
const HANDLE MultiReader::hReaderSemaphore = CreateSemaphore( NULL, 1, 1, NULL);
 
void MultiReader::CreateThreads()
{
	unsigned int nThreadNo;
	for( nThreadNo = 0; nThreadNo < vDirectories.size(); nThreadNo++)
	{
		CreateThread( NULL, 0, MultiReader::ReaderThread, (void*)&vDirectories.at(nThreadNo), 0, NULL);
	}
} //it works and these variables are defined in derived class
 
WORD WINAPI MultiReader::ReaderThread(LPVOID p_pVoid)
{
 
	WaitForSingleObject( hReaderSemaphore, 0);
 
	OPTIONS* ThreadData = (OPTIONS*) p_pVoid;
	cout << ThreadData->sDirectoryName << endl;
	cout << ThreadData->uOperationId << endl;
	DisplayVector(ThreadData->vExtensions);
	cout << endl;
 
	ReleaseSemaphore( hReaderSemaphore, 1, NULL );
	return NULL;
}

// *.h file
#include <vector>
#include <string>
class foo
{
public:
   static std::vector<std::string> lst;
   // other stuff not shown
};

// *.cpp file
#include "foo.h"
std::vector<std::string> foo::lst;

int main()
{
    return 0;
}