diff --git a/IlmImf/ImfHeader.h b/IlmImf/ImfHeader.h
index 756a62e..dd71e0e 100644
--- a/IlmImf/ImfHeader.h
+++ b/IlmImf/ImfHeader.h
@@ -493,7 +493,7 @@ class Header::ConstIterator
 //
 //------------------------------------------------------------------------
 
-void staticInitialize ();
+IMF_EXPORT void staticInitialize ();
 
 
 //-----------------