-#define phpstr_init(b) phpstr_init_ex(b, 0, 0)
-#define phpstr_clone(phpstr_pointer) phpstr_init_ex(NULL, (phpstr_pointer)->size, 0)
-PHPSTR_API phpstr *phpstr_init_ex(phpstr *buf, size_t chunk_size, int pre_alloc);
+#define phpstr_init(b) phpstr_init_ex(b, PHPSTR_DEFAULT_SIZE, 0)
+#define phpstr_clone(phpstr_pointer) phpstr_init_ex(NULL, (phpstr_pointer)->size, (phpstr_pointer)->pmem ? PHPSTR_INIT_PERSISTENT:0)
+PHPSTR_API phpstr *phpstr_init_ex(phpstr *buf, size_t chunk_size, int flags);