-extern size_t triple_hash (void const *x, size_t table_size);
-extern size_t triple_hash_no_name (void const *x, size_t table_size);
+extern size_t triple_hash (void const *x, size_t table_size) _GL_ATTRIBUTE_PURE;
+extern size_t triple_hash_no_name (void const *x, size_t table_size)
+ _GL_ATTRIBUTE_PURE;