stream_set_chunk_size Set the stream chunk size &reftitle.description; intstream_set_chunk_size resourcefp intchunk_size Set the stream chunk size. &reftitle.parameters; fp The target stream. chunk_size The desired new chunk size. &reftitle.returnvalues; Returns the previous chunk size on success. Will return &false; if chunk_size is less than 1 or greater than PHP_INT_MAX. &reftitle.errors; Will emit an E_WARNING level error if chunk_size is less than 1 or greater than PHP_INT_MAX.