USER_ERROR        647 contrib/libtests/pngimage.c          case USER_ERROR:     lp = "error(user)"; break;
USER_ERROR        711 contrib/libtests/pngimage.c          display_log(dp, USER_ERROR, "open failed: %s", strerror(errno));
USER_ERROR        739 contrib/libtests/pngimage.c          display_log(dp, USER_ERROR, "file truncated (%lu bytes)",