Re: STL Map Scoping Issue

From:

Frank Birbacher <bloodymir.crap@gmx.net>

Newsgroups:

comp.lang.c++

Date:

Sun, 12 Aug 2007 19:22:48 +0200

Message-ID:

<5i8u7uF3mnoniU1@mid.dfncis.de>

Hi!

sfncook@gmail.com schrieb:

Wow! You guys are great! Thanks for the responses so far. However, I
forgot to mention one factor that must make the difference: The code
is broken up into different files.

Indeed that is the difference, as Gianni already pointed out. :)

********* typedefs.h *****************
#include "stdlib.h"
#include <map>
#include <vector>

typedef struct _ShipType {
    int a;
    int b;
    int c;
} ShipType;

static std::map<int, ShipType *> shipTypeMap;

This definition of shipTypeMap includes "static". That makes shipTypeMap
appear mutiple times: once for each translation unit (= cpp file). So
your initialisation code initialises one instance while the other code
accesses the uninitialised one => oops. You need to do the following:

typedefs.h:
extern std::map<int, ShipType*> shipTypeMap;

somewhere.cpp:
std::map<int, ShipType*> shipTypeMap;

This makes one global instance of shipTypeMap which is then access from
all code.

HTH,
Frank