# nng_http_conn_write_all(3http) Manual Page

## NAME

nng_http_conn_write_all - write all to HTTP connection

## SYNOPSIS

    #include <nng/nng.h>
    #include <nng/supplemental/http/http.h>

    void nng_http_conn_write_all(nng_http_conn *conn, nng_aio *aio);

## DESCRIPTION

The `nng_http_conn_write_all()` function starts an asynchronous write to the HTTP connection conn, into the scatter/gather vector located in the asynchronous I/O structure aio.

| The `nng_aio_set_iov()` function must have been called first, to set the scatter/gather vector for aio.

This function returns immediately, with no return value. Completion of the operation is signaled via the aio, and the final result may be obtained via `nng_aio_result()`. That result will either be zero or an error code.

The I/O operation completes only when the entire amount of data requested has been written, or an error has occurred. If the operation completes successfully, then the entire requested data has been written.

It is still possible for a partial write to complete in the event of an error. The actual number of bytes written can be determined with `nng_aio_count()`.

| The main purpose for this function is to facilitate writing HTTP body content.

| Usually an HTTP request or response will have been written immediately prior to this with `http_conn_write_req()` or `http_conn_write_res()`. In that case the request or response should have also contained an `Content-Length` header, and possibly a `Content-Type` header.

| An easier solution to sending HTTP content data, is to include the content with the request or reply using a function like `nng_http_req_copy_data()`. In that case, the body data will be written automatically by the `http_conn_write_req()` or `http_conn_write_res()` function.

## RETURN VALUES

None.

## ERRORS

`NNG_ECANCELED` | The operation was canceled.
`NNG_ECLOSED` | The connection was closed.
`NNG_ECONNRESET` | The peer closed the connection.
`NNG_EINVAL` | The aio does not contain a valid scatter/gather vector.
`NNG_ENOMEM` | Insufficient free memory to perform the operation.
`NNG_ENOTSUP` | HTTP operations are not supported.
`NNG_ETIMEDOUT` | Timeout waiting for data from the connection.

## SEE ALSO

nng_aio_alloc(3), nng_aio_count(3), nng_aio_result(3), nng_aio_set_iov(3), nng_http_client_connect(3http), nng_http_conn_write(3http), http_conn_write_req(3http), http_conn_write_res(3http), nng_http_req_copy_data(3http), nng_http_req_set_data(3http), nng_http_res_copy_data(3http), nng_http_res_set_data(3http), nng_strerror(3), nng(7)