http::async_write_header

Write a header to a stream asynchronously using a serializer.

Synopsis

Defined in header <boost/beast/http/write.hpp>

template<
    class AsyncWriteStream,
    bool isRequest,
    class Body,
    class Fields,
    class WriteHandler = net::default_completion_token_t<            executor_type<AsyncWriteStream>>>
DEDUCED
async_write_header(
    AsyncWriteStream& stream,
    serializer< isRequest, Body, Fields >& sr,
    WriteHandler&& handler = net::default_completion_token_t< executor_type< AsyncWriteStream >>{});

This function is used to write a header to a stream asynchronously using a caller-provided HTTP/1 serializer. The function call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:

The function serializer::is_header_done returns true
An error occurs.

This operation is implemented in terms of zero or more calls to the stream's async_write_some function, and is known as a composed operation. The program must ensure that the stream performs no other writes until this operation completes.

Parameters

Name	Description
`stream`	The stream to which the data is to be written. The type must support the AsyncWriteStream concept.
`sr`	The serializer to use. The object must remain valid at least until the handler is called; ownership is not transferred.
`handler`	The completion handler to invoke when the operation completes. The implementation takes ownership of the handler by performing a decay-copy. The equivalent function signature of the handler must be: void handler( error_code const& error, // result of operation std::size_t bytes_transferred // the number of bytes written to the stream ); Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using `net::post`.

Name

Description

stream

The stream to which the data is to be written. The type must support the AsyncWriteStream concept.

sr

The serializer to use. The object must remain valid at least until the handler is called; ownership is not transferred.

handler

The completion handler to invoke when the operation completes. The implementation takes ownership of the handler by performing a decay-copy. The equivalent function signature of the handler must be:

void handler(
    error_code const& error,        // result of operation
    std::size_t bytes_transferred   // the number of bytes written to the stream
);

Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using net::post.

Remarks

The implementation will call serializer::split with the value true on the serializer passed in.

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