You may experience an access violation when you access an STL object through a pointer or reference in a different DLL or EXE

   //---------------------------------------------------------
   // AVEXE.CPP
   // Compile options needed: /GX
   #pragma warning (disable : 4786)
   #include <map>
   #include <string>
   #include <stdio.h>

   __declspec(dllimport)
   std::map<int,std::string>* GiveMeAMap(int n);

   __declspec(dllimport)
   void ShowMeTheMap(std::map<int,std::string> *amap);

   __declspec(dllexport)
   const char* MapItemX (std::map<int,std::string> *m, int x);

   int main () {

      // Create the map in the DLL
      int x = 6;
      std::map<int,std::string> *p = GiveMeAMap(x);

      // Display the contents of the map from the DLL
      printf("Showing contents from the DLL\n");
      ShowMeTheMap(p);

      // Display the contents of the map from the EXE
      // using the accessor function from the DLL so we
      // aren‘t directly accessing the map
      printf("Showing contents from the EXE using accessor\n");
      int i = x;
      while (i--) {
         printf("%d = %s\n",i,MapItemX(p,i));
      }

      // Access Violation when accessing the map that
      // was created in the DLL from the EXE
      printf("Showing contents from the EXE directly\n");
      while (x--) {
         printf("%d = %s\n",x,(*p)[x].c_str());
      }

      return 0;
   }

   //---------------------------------------------------------
   // AVDLL.CPP
   // Compile options needed /GX
   #pragma warning (disable : 4786)
   #include <map>
   #include <string>
   #include <stdlib.h>

   // Create the map here in the DLL
   __declspec(dllexport)
   std::map<int,std::string>* GiveMeAMap(int n) {
      std::map<int,std::string> *m = new std::map<int,std::string>;
      while(n--) {
         char b[33];
         itoa(n,b,2);
         (*m)[n] = std::string(b);
      }
      return m;
   }

   // We can access the map without error from the executable
   // image where the map was created
   __declspec(dllexport)
   void ShowMeTheMap(std::map<int,std::string> *p) {
      int x = p->size();
      while (x--) {
         printf("%d = %s\n",x,(*p)[x].c_str());
      }
   }

   // An accessor method to return the associated C string
   // for key x
   __declspec(dllexport)
   const char* MapItemX (std::map<int,std::string> *m, int x) {
      return (*m)[x].c_str();
   }