ZSTD_getErrorCode
ZSTDLIB_API ZSTD_ErrorCode ZSTD_getErrorCode(size_t functionResult); /* convert a result into an error code, which can be compared to error enum list */
(ZSTD_getErrorCode(res) == ZSTD_error_prefix_unknown)
EXPORT_SYMBOL_GPL(ZSTD_getErrorCode);
return ZSTD_getErrorCode(code);