diff --git a/hypopg.c b/hypopg.c
index 419938a..3153e78 100644
--- a/hypopg.c
+++ b/hypopg.c
@@ -31,10 +31,10 @@ MemoryContext HypoMemoryContext;
 
 /*--- Functions --- */
 
-void		_PG_init(void);
-void		_PG_fini(void);
+PGDLLEXPORT void		_PG_init(void);
+PGDLLEXPORT void		_PG_fini(void);
 
-Datum		hypopg_reset(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_reset(PG_FUNCTION_ARGS);
 
 PG_FUNCTION_INFO_V1(hypopg_reset);
 
@@ -334,7 +334,7 @@ hypo_get_relation_info_hook(PlannerInfo *root,
 /*
  * Reset statistics.
  */
-Datum
+PGDLLEXPORT Datum
 hypopg_reset(PG_FUNCTION_ARGS)
 {
 	hypo_index_reset();
diff --git a/hypopg_index.c b/hypopg_index.c
index 935817b..ed97529 100644
--- a/hypopg_index.c
+++ b/hypopg_index.c
@@ -1668,8 +1668,7 @@ hypo_estimate_index(hypoIndex *entry, RelOptInfo *rel)
 			  - (fillfactor == 0 ? BTREE_DEFAULT_FILLFACTOR : fillfactor)
 						+ additional_bloat) / 100;
 
-		entry->pages =
-			entry->tuples * line_size * bloat_factor / usable_page_size;
+		entry->pages = (BlockNumber) (entry->tuples * line_size * bloat_factor / usable_page_size);
 #if PG_VERSION_NUM >= 90300
 		entry->tree_height = -1;	/* TODO */
 #endif
@@ -1751,7 +1750,7 @@ hypo_estimate_index(hypoIndex *entry, RelOptInfo *rel)
 			sizeof_SignType * bloomLength;
 
 		entry->pages = 1; /* meta page */
-		entry->pages += ceil(
+		entry->pages += (BlockNumber) ceil(
 				((double) entry->tuples * line_size) / usable_page_size);
 	}
 #endif
diff --git a/include/hypopg_index.h b/include/hypopg_index.h
index fc00af1..3738533 100644
--- a/include/hypopg_index.h
+++ b/include/hypopg_index.h
@@ -111,12 +111,12 @@ extern List	   *hypoIndexes;
 
 void hypo_index_reset(void);
 
-Datum		hypopg(PG_FUNCTION_ARGS);
-Datum		hypopg_create_index(PG_FUNCTION_ARGS);
-Datum		hypopg_drop_index(PG_FUNCTION_ARGS);
-Datum		hypopg_relation_size(PG_FUNCTION_ARGS);
-Datum		hypopg_get_indexdef(PG_FUNCTION_ARGS);
-Datum		hypopg_reset_index(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_create_index(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_drop_index(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_relation_size(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_get_indexdef(PG_FUNCTION_ARGS);
+PGDLLEXPORT Datum		hypopg_reset_index(PG_FUNCTION_ARGS);
 
 extern explain_get_index_name_hook_type prev_explain_get_index_name_hook;
 const char *hypo_explain_get_index_name_hook(Oid indexId);