## Class template basic_exception_handler_logger

boost::log::sources::basic_exception_handler_logger — Exception handler feature implementation.

## Synopsis

    // In header: <boost/log/sources/exception_handler_feature.hpp>

    template<typename BaseT>
    class basic_exception_handler_logger : public BaseT {
    public:
      // types
      typedef base_type::threading_model                                                              threading_model;         // Threading model being used.
      typedef base_type::final_type                                                                   final_type;              // Final logger type.
      typedef unspecified                                                                             exception_handler_type;  // Exception handler function type.
      typedef strictest_lock< typenamebase_type::open_record_lock, no_lock< threading_model > >::type open_record_lock;        // Lock requirement for the open_record_unlocked method.
      typedef strictest_lock< typenamebase_type::push_record_lock, no_lock< threading_model > >::type push_record_lock;        // Lock requirement for the push_record_unlocked method.
      typedef unspecified                                                                             swap_lock;               // Lock requirement for the swap_unlocked method.

      // public member functions
      basic_exception_handler_logger();
      basic_exception_handler_logger(basic_exception_handler_logger const &);
      basic_exception_handler_logger(basic_exception_handler_logger &&);
      template<typename ArgsT>
        explicit basic_exception_handler_logger(ArgsT const &);
      template<typename HandlerT> void set_exception_handler(HandlerT const &);

      // protected member functions
      template<typename ArgsT> record open_record_unlocked(ArgsT const &);
      void push_record_unlocked(record &&);
      void swap_unlocked(basic_exception_handler_logger &);
    };

## Description

### `basic_exception_handler_logger` public member functions

1.     basic_exception_handler_logger();

   Default constructor. The constructed logger does not have an exception handler.

2.     basic_exception_handler_logger(basic_exception_handler_logger const & that);

   Copy constructor

3.     basic_exception_handler_logger(basic_exception_handler_logger && that);

   Move constructor

4.     template<typename ArgsT>
         explicit basic_exception_handler_logger(ArgsT const & args);

   Constructor with arguments. Passes arguments to other features.

5.     template<typename HandlerT>
         void set_exception_handler(HandlerT const & handler);

   The method sets exception handler function. The function will be called with no arguments in case if an exception occurs during either `open_record` or `push_record` method execution. Since exception handler is called from a `catch` statement, the exception can be rethrown in order to determine its type.

   By default no handler is installed, thus any exception is propagated as usual.

   See Also: `utility/exception_handler.hpp`

   | Note
   The exception handler can be invoked in several threads concurrently.

   | Note
   Thread interruptions are not affected by exception handlers.

   Parameters:

   `handler` | Exception handling function

### `basic_exception_handler_logger` protected member functions

1.     template<typename ArgsT> record open_record_unlocked(ArgsT const & args);

   Unlocked `open_record`

2.     void push_record_unlocked(record && rec);

   Unlocked `push_record`

3.     void swap_unlocked(basic_exception_handler_logger & that);

   Unlocked swap