diff --git a/src/runtime/c/pgf/pgf.h b/src/runtime/c/pgf/pgf.h
index f4777b641..6d5cea5ac 100644
--- a/src/runtime/c/pgf/pgf.h
+++ b/src/runtime/c/pgf/pgf.h
@@ -13,8 +13,8 @@
 #define PGF_API_DECL EXTERN_C __declspec(dllexport)
 #define PGF_API      EXTERN_C __declspec(dllexport)
 #elif defined(COMPILING_STATIC_PGF)
-#define PGF_API_DECL
-#define PGF_API
+#define PGF_API_DECL EXTERN_C
+#define PGF_API      EXTERN_C
 #else
 #define PGF_API_DECL __declspec(dllimport)
 #define PGF_API      ERROR_NOT_COMPILING_LIBPGF