在dll中找不到名为*的入口点

typedef enum                        /* Set operation type                */
{
  GPC_DIFF,                         /* Difference                        */
  GPC_INT,                          /* Intersection                      */
  GPC_XOR,                          /* Exclusive or                      */
  GPC_UNION                         /* Union                             */
} gpc_op;

typedef struct                      /* Polygon vertex structure          */
{
  double              x;            /* Vertex x component                */
  double              y;            /* vertex y component                */
} gpc_vertex;

typedef struct                      /* Vertex list structure             */
{
  int                 num_vertices; /* Number of vertices in list        */
  gpc_vertex         *vertex;       /* Vertex array pointer              */
} gpc_vertex_list;

typedef struct                      /* Polygon set structure             */
{
  int                 num_contours; /* Number of contours in polygon     */
  int                *hole;         /* Hole / external contour flags     */
  gpc_vertex_list    *contour;      /* Contour array pointer             */
} gpc_polygon;

void gpc_polygon_clip        (gpc_op           set_operation,
                              gpc_polygon     *subject_polygon,
                              gpc_polygon     *clip_polygon,
                              gpc_polygon     *result_polygon);

我在VS2008中编译了它。它可以编译!到现在为止,一直都还不错。

下一步我想从.NET调用C++ DLL,我做一个标准PInvoke:

[DllImport("gpc.dll")]
private static extern void gpc_polygon_clip([In]     GpcOperation set_operation,
                                            [In]     ref gpc_polygon subject_polygon,
                                            [In]     ref gpc_polygon clip_polygon,
                                            [In, Out] ref gpc_polygon result_polygon);

我认为我的C++ VcPROJ设置一定是错误的,因为它似乎没有导出定义。你知道怎么解决吗?