key_regexp = (regex_t*)xmalloc(sizeof(regex_t));
                if (regcomp(key_regexp, key, REG_EXTENDED)) {
                        error("invalid key pattern: %s", key_);
-                       free(key_regexp);
-                       key_regexp = NULL;
+                       FREE_AND_NULL(key_regexp);
                        ret = CONFIG_INVALID_PATTERN;
                        goto free_strings;
                }
                regexp = (regex_t*)xmalloc(sizeof(regex_t));
                if (regcomp(regexp, regex_, REG_EXTENDED)) {
                        error("invalid pattern: %s", regex_);
-                       free(regexp);
-                       regexp = NULL;
+                       FREE_AND_NULL(regexp);
                        ret = CONFIG_INVALID_PATTERN;
                        goto free_strings;
                }