# mongoc_stream_writev()

## Synopsis

    ssize_t
    mongoc_stream_writev (mongoc_stream_t *stream,
                          mongoc_iovec_t *iov,
                          size_t iovcnt,
                          int32_t timeout_msec);

## Parameters

- `stream`: A mongoc_stream_t.

- `iov`: A vector of mongoc_iovec_t.

- `iovcnt`: The number of items in `iov`.

- `timeout_msec`: The number of milliseconds to block before indicating failure, or 0 for non-blocking. Negative values indicate the default timeout.

The `mongoc_stream_writev()` function shall perform a write to a mongoc_stream_t. It’s modeled on the API and semantics of `writev()`, though the parameters map only loosely.

## Returns

The number of bytes written on success, or `-1` upon failure and `errno` is set.