diff --git a/vl/generic.c b/vl/generic.c
index c6f84a9..8617ed2 100644
--- a/vl/generic.c
+++ b/vl/generic.c
@@ -1513,13 +1513,13 @@ vl_thread_specific_state_delete (VlThreadState * self)
  */
 
 #if (defined(VL_OS_LINUX) || defined(VL_OS_MACOSX)) && defined(VL_COMPILER_GNUC)
-static void vl_constructor () __attribute__ ((constructor)) ;
-static void vl_destructor () __attribute__ ((destructor))  ;
+//static void vl_constructor () __attribute__ ((constructor)) ;
+//static void vl_destructor () __attribute__ ((destructor))  ;
 #endif
 
 #if defined(VL_OS_WIN)
-static void vl_constructor () ;
-static void vl_destructor () ;
+//static void vl_constructor () ;
+//static void vl_destructor () ;
 
 BOOL WINAPI DllMain(
     HINSTANCE hinstDLL,  // handle to DLL module
@@ -1563,7 +1563,7 @@ BOOL WINAPI DllMain(
 /* ---------------------------------------------------------------- */
 
 /** @internal @brief Initialize VLFeat state */
-static void
+void
 vl_constructor (void)
 {
   VlState * state ;
@@ -1637,7 +1637,7 @@ vl_constructor (void)
 }
 
 /** @internal @brief Destruct VLFeat */
-static void
+void
 vl_destructor ()
 {
   VlState * state ;
diff --git a/vl/generic.h b/vl/generic.h
index 4ef87f2..30a974e 100644
--- a/vl/generic.h
+++ b/vl/generic.h
@@ -206,5 +206,7 @@ VL_EXPORT double vl_toc (void) ;
 VL_EXPORT double vl_get_cpu_time (void) ;
 /** @} */
 
+VL_EXPORT void vl_constructor();
+VL_EXPORT void vl_destructor();
 /* VL_GENERIC_H */
 #endif
diff --git a/vl/sift.c b/vl/sift.c
index 03963fe..6477a81 100644
--- a/vl/sift.c
+++ b/vl/sift.c
@@ -1443,7 +1443,7 @@ vl_sift_detect (VlSiftFilt * f)
  ** @remark The minimum octave size is 2x2xS.
  **/
 
-static void
+void
 update_gradient (VlSiftFilt *f)
 {
   int       s_min = f->s_min ;
diff --git a/vl/sift.h b/vl/sift.h
index 50e03f4..f9558ad 100644
--- a/vl/sift.h
+++ b/vl/sift.h
@@ -138,7 +138,8 @@ void  vl_sift_keypoint_init              (VlSiftFilt const *f,
                                           double y,
                                           double sigma) ;
 /** @} */
-
+VL_EXPORT
+void update_gradient(VlSiftFilt* f);
 /** @name Retrieve data and parameters
  ** @{
  **/