PS_UNDEF_MARKER   966 ext/session/session.c 			if (memchr(key, PS_DELIMITER, key_length) || memchr(key, PS_UNDEF_MARKER, key_length)) {
PS_UNDEF_MARKER   975 ext/session/session.c 			smart_str_appendc(&buf, PS_UNDEF_MARKER);
PS_UNDEF_MARKER  1011 ext/session/session.c 		if (p[0] == PS_UNDEF_MARKER) {