///===== this is in my header

class NET_MESSAGE_MAKER; //forward decl

typedef map netMessageMakerMap;


class NET_MESSAGE_MAKER
{
public:
NET_MESSAGE_MAKER(unsigned long int type)
{
//registry.insert(std::make_pair(type, this));
registry.insert(netMessageMakerMap::value_type(type, this));
}
~NET_MESSAGE_MAKER(){}

static NET_MESSAGE *constructMessage( uchar *data, int datasize);

protected:
static netMessageMakerMap registry;
virtual NET_MESSAGE *makeMessage( uchar *data, int datasize) const = 0;

};

//============= this is one of the derivative classes in
//============= the source file, specifically for login
//============= request message maker, where NM_LOGIN_REQUEST
//============= is defined in another header.

class cNM_LoginRequestMaker : public NET_MESSAGE_MAKER
{
private:
NET_MESSAGE *makeMessage( uchar *data, int datasize) const
{
NET_MESSAGE *msg = NULL;
try
{
msg = new NM_LOGIN_REQUEST;
msg->serializeFrom(data, datasize);
}
catch (...)
{
delete msg;
throw;
}
return msg;
}
static const cNM_LoginRequestMaker registerthis;
//automatically forces constructor of NET_MESSAGE_MAKER
//to insert into the map (supposedly)
public:
cNM_LoginRequestMaker() : NET_MESSAGE_MAKER(1) {}

};


//==== this is in the same source file, the implementation
//==== of constructmessage

NET_MESSAGE *NET_MESSAGE_MAKER::constructMessage( uchar *data, int datasize )
{
//first character is the message id;
uchar msgID = *data;


// find the appropriate factory in the map of factories...
//aa: this registry seems to not like being used as protected, though it should work
//NET_MESSAGE_MAKER *maker = (*registry.find(msgID)).second;
NET_MESSAGE_MAKER *maker = (*registry.find(msgID)).second;
if( !maker )
return NULL;


// use that factory to construct the net_message derivative
return maker->makeMessage( data, datasize );

}

//and the error is an unresolved external for the protected static map

however, looking through adrian perez''s code, i see he used:

netMessageMakerMap NET_MESSAGE_MAKER::registry = netMessageMakerMap();

before defining any of the derivative classes, which would i assume instantiates the registry to a new netMessageMakerMap.

now, if i did that, it would compile and link, but when i step through the constructMessage function and it attempts to find a messagemaker in the map of message makers, the pointer becomes null (or 0xcdcdcdcd in debug), which indicates to me that the static registry was not initialized (inserted) properly.

any more specifics, i''ll be glad to add, but this should start people off...

a2k