diff --git a/src/db_transaction.c b/src/db_transaction.c
index cd8eb08..308de30 100644
--- a/src/db_transaction.c
+++ b/src/db_transaction.c
@@ -52,4 +52,4 @@ int transactionRollback(struct stored_conn_t *sconn)
   }
   sconn->inTransaction = 0;
   return 0;
-}
\ No newline at end of file
+}
diff --git a/src/db_value.c b/src/db_value.c
index 6c0feed..2b04d13 100644
--- a/src/db_value.c
+++ b/src/db_value.c
@@ -6,8 +6,8 @@
 #include <errno.h>
 #include <mysql.h>
 
-#include "strext.h"
 #include "db_value.h"
+#include "strext.h"
 
 char *db_value(char **str, size_t *len, e_column_type type, uint32_t n_args, ...)
 {
diff --git a/src/db_where-builder_p.h b/src/db_where-builder_p.h
index c85d689..780823a 100644
--- a/src/db_where-builder_p.h
+++ b/src/db_where-builder_p.h
@@ -3,6 +3,18 @@
 
 #include "db_where-builder.h"
 
+#ifndef DLL_LOCAL
+#  if defined _WIN32 || defined __CYGWIN__
+#    define DLL_LOCAL
+#  else
+#    if __GNUC__ >= 4
+#      define DLL_LOCAL  __attribute__ ((visibility ("hidden")))
+#    else
+#      define DLL_LOCAL
+#    endif
+#  endif
+#endif
+
 struct where_logic_t {
   where_builder *up;
   e_where_logic logic_type;
@@ -36,24 +48,32 @@ struct where_clause_t {
 };
 typedef struct where_clause_t where_clause;
 
-
+DLL_LOCAL
 where_logic *createLogic(e_where_logic type, size_t initial_size);
+DLL_LOCAL
 int compileLogic(where_logic *logic, char **str, size_t *str_len);
+DLL_LOCAL
 void freeLogic(where_logic **logic_ptr);
 
+DLL_LOCAL
 where_builder *appendLogicClause(where_builder *wb, where_builder *wb_clause);
 
-
+DLL_LOCAL
 where_clause *createWhere(const char *tbl, const char *col, e_where_op op);
+DLL_LOCAL
 int compileWhere(where_clause *clause, char **str, size_t *str_len);
+DLL_LOCAL
 void freeWhere(where_clause **where_ptr);
 
+DLL_LOCAL
 int ensureWhereValueSize(where_clause *clause, size_t new_size);
 
-
+DLL_LOCAL
 where_builder *where_And_Or(where_builder *wb, where_builder *wb_clause, e_where_logic and_or);
+DLL_LOCAL
 where_builder *where_In_notIn(where_builder *wb, const char *tbl, const char *col, e_where_op op,
                               e_column_type type, uint32_t n_args, ...);
+DLL_LOCAL
 where_builder *where_In_notIn_va(where_builder *wb, const char *tbl, const char *col, e_where_op op,
                                  e_column_type type, uint32_t n_args, va_list args);