Class template asynchronous

Class template asynchronous_sink

boost::log::sinks::asynchronous_sink — Asynchronous logging sink frontend.

Synopsis

// In header: <boost/log/sinks/async_frontend.hpp>

template<typename SinkBackendT> 
class asynchronous_sink :
  public asynchronous_frontend< SinkBackendT::char_type >
{
public:
  // types
  typedef SinkBackendT           sink_backend_type;   // Sink implementation type. 
  typedef base_type::char_type   char_type;           // Character type. 
  typedef base_type::record_type record_type;         // Log record type. 
  typedef base_type::string_type string_type;         // String type to be used as a message text holder. 
  typedef implementation_defined locked_backend_ptr;  // A pointer type that locks the backend until it's destroyed. 

  // construct/copy/destruct
  asynchronous_sink(bool = true);
  explicit asynchronous_sink(shared_ptr< sink_backend_type > const &, 
                             bool = true);

  // public member functions
  locked_backend_ptr locked_backend() const;
  void run();
  bool stop();
  void feed_records();
};

Description

The frontend starts a separate thread on construction. All logging records are passed to the backend in this dedicated thread only.

`asynchronous_sink` public construct/copy/destruct

asynchronous_sink(bool start_thread = true);

Default constructor. Constructs the sink backend instance. Requires the backend to be default-constructible.

Parameters:

start_thread

If true, the frontend creates a thread to feed log records to the backend. Otherwise no thread is started and it is assumed that the user will call either run or feed_records himself.

explicit asynchronous_sink(shared_ptr< sink_backend_type > const & backend, 
                           bool start_thread = true);

Constructor attaches user-constructed backend instance

Parameters:

`backend`	Pointer to the backend instance.
`start_thread`	If `true`, the frontend creates a thread to feed log records to the backend. Otherwise no thread is started and it is assumed that the user will call either `run` or `feed_records` himself.

Requires:

backend is not NULL.

`asynchronous_sink` public member functions

locked_backend_ptr locked_backend() const;

Locking accessor to the attached backend

```
void run();
```
The method starts record feeding loop and effectively blocks until either of this happens:
- the thread is interrupted due to either standard thread interruption or a call to stop
- an exception is thrown while processing a log record in the backend, and the exception is not terminated by the exception handler, if one is installed
Requires:
The sink frontend must be constructed without spawning a dedicated thread

bool stop();

The method softly interrupts record feeding loop. This method must be called when the run method execution has to be interrupted. Unlike regular thread interruption, calling stop will not interrupt the record processing in the middle. Instead, the sink frontend will attempt to finish its business (including feeding the rest of the buffered records to the backend) and return afterwards. This method can be called either if the sink was created with a dedicated thread, or if the run method was called by user.

Note

	Note
Returning from this method does not guarantee that there are no records left buffered in the sink frontend. It is possible that log records keep coming during and after this method is called. At some point of execution of this method log records stop being processed, and all records that come after this point are put into the queue. These records will be processed upon further calls to `run` or `feed_records`.

Returning from this method does not guarantee that there are no records left buffered in the sink frontend. It is possible that log records keep coming during and after this method is called. At some point of execution of this method log records stop being processed, and all records that come after this point are put into the queue. These records will be processed upon further calls to run or feed_records.

```
void feed_records();
```
The method feeds log records that may have been buffered to the backend and returns

Requires:
The sink frontend must be constructed without spawning a dedicated thread