STL의 map 자료구조 thread-safe 한가요?

class CFoo
{
public:
   CFoo();
   virtual ~CFoo();
 
protected:
   int    m_nMember1;
   char  *m_pszMember1;
   string m_strMember1;
   string m_strMember2;
   ... someting else ....
}
 
int main()
{
   map<int, CFoo> g_data;         <=== 전역변수임.
 
   g_data[1111] = foo1;           <=== 초기화
   g_data[2222] = foo2;           <=== 초기화
   g_data[3333] = foo3;           <=== 초기화
 
   return 0;
}
 
bool Find(int nKey, CFoo &ret)    <=== 전역함수임.
{
    map<int, CFoo>::const_iterator iter = g_data.find(nKey);
 
    if ( iter == g_data.end() )
         return false;
 
    ret = iter->second;
 
    // if i play with 'iter->second' in multi-thread environment,
    // am i crazy or not ?
}
 
void 쓰레드()
{
    CFoo f;
 
    if ( Find(111,f) )
    {
          // play with 'f';
    }
}