diff --git a/ext/digest/digest.c b/ext/digest/digest.c
index 28f6022..f0f0910 100644
--- a/ext/digest/digest.c
+++ b/ext/digest/digest.c
@@ -13,6 +13,7 @@
 
 ************************************************/
 
+#define RB_DIGEST_WRAP_METADATA_LINKAGE RUBY_FUNC_EXPORTED
 #include "digest.h"
 
 static VALUE rb_mDigest;
@@ -543,7 +544,7 @@ static const rb_data_type_t metadata_type = {
     {0},
 };
 
-RUBY_FUNC_EXPORTED VALUE
+RB_DIGEST_WRAP_METADATA_LINKAGE VALUE
 rb_digest_wrap_metadata(const rb_digest_metadata_t *meta)
 {
     return rb_obj_freeze(TypedData_Wrap_Struct(0, &metadata_type, (void *)meta));
diff --git a/ext/digest/digest.h b/ext/digest/digest.h
index c5c3758..0ad8df6 100644
--- a/ext/digest/digest.h
+++ b/ext/digest/digest.h
@@ -73,13 +73,21 @@ rb_id_metadata(void)
 # define DIGEST_USE_RB_EXT_RESOLVE_SYMBOL 1
 #endif
 
+/* Declarations and definitions of the same function must carry the same
+ * attribute on MSVC, and digest.c has to export the definition so that
+ * statically linked extensions can find the symbol in libruby. */
+#ifndef RB_DIGEST_WRAP_METADATA_LINKAGE
+# define RB_DIGEST_WRAP_METADATA_LINKAGE extern
+#endif
+
 static inline VALUE
 rb_digest_make_metadata(const rb_digest_metadata_t *meta)
 {
 #if defined(EXTSTATIC) && EXTSTATIC
     /* The extension is built as a static library, so safe to refer to
      * rb_digest_wrap_metadata directly. */
-    extern VALUE rb_digest_wrap_metadata(const rb_digest_metadata_t *meta);
+    RB_DIGEST_WRAP_METADATA_LINKAGE
+    VALUE rb_digest_wrap_metadata(const rb_digest_metadata_t *meta);
     return rb_digest_wrap_metadata(meta);
 #else
     /* The extension is built as a shared library, so we can't refer