## Function channel_severity_filter

boost::log::expressions::channel_severity_filter

## Synopsis

    // In header: <boost/log/expressions/predicates/channel_severity_filter.hpp>

    template<typename ChannelT, typename SeverityT>
      channel_severity_filter_actor< ChannelT, SeverityT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_name const & severity_name);
    template<typename SeverityT, typename ChannelDescriptorT,
             template< typename > class ActorT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, SeverityT, fallback_to_none, fallback_to_none, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_name const & severity_name);
    template<typename ChannelT, typename SeverityDescriptorT,
             template< typename > class ActorT>
      channel_severity_filter_actor< ChannelT, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword);
    template<typename ChannelDescriptorT, typename SeverityDescriptorT,
             template< typename > class ActorT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword);
    template<typename SeverityT, typename ChannelT, typename ChannelFallbackT,
             typename ChannelTagT, template< typename > class ActorT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, fallback_to_none, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_name const & severity_name);
    template<typename ChannelT, typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT>
      channel_severity_filter_actor< ChannelT, SeverityT, fallback_to_none, SeverityFallbackT, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder);
    template<typename ChannelT, typename ChannelFallbackT, typename ChannelTagT,
             typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, SeverityFallbackT, less, greater_equal, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder);
    template<typename ChannelT, typename SeverityT, typename SeverityCompareT>
      channel_severity_filter_actor< ChannelT, SeverityT, fallback_to_none, fallback_to_none, less, SeverityCompareT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare);
    template<typename SeverityT, typename ChannelDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, SeverityT, fallback_to_none, fallback_to_none, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare);
    template<typename ChannelT, typename SeverityDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT>
      channel_severity_filter_actor< ChannelT, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword,
                              SeverityCompareT const & severity_compare);
    template<typename ChannelDescriptorT, typename SeverityDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword,
                              SeverityCompareT const & severity_compare);
    template<typename SeverityT, typename ChannelT, typename ChannelFallbackT,
             typename ChannelTagT, template< typename > class ActorT,
             typename SeverityCompareT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, fallback_to_none, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare);
    template<typename ChannelT, typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT,
             typename SeverityCompareT>
      channel_severity_filter_actor< ChannelT, SeverityT, fallback_to_none, SeverityFallbackT, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder,
                              SeverityCompareT const & severity_compare);
    template<typename ChannelT, typename ChannelFallbackT, typename ChannelTagT,
             typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT,
             typename SeverityCompareT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, SeverityFallbackT, less, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder,
                              SeverityCompareT const & severity_compare);
    template<typename ChannelT, typename SeverityT, typename SeverityCompareT,
             typename ChannelOrderT>
      channel_severity_filter_actor< ChannelT, SeverityT, fallback_to_none, fallback_to_none, ChannelOrderT, SeverityCompareT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename SeverityT, typename ChannelDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT,
             typename ChannelOrderT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, SeverityT, fallback_to_none, fallback_to_none, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename ChannelT, typename SeverityDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT,
             typename ChannelOrderT>
      channel_severity_filter_actor< ChannelT, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename ChannelDescriptorT, typename SeverityDescriptorT,
             template< typename > class ActorT, typename SeverityCompareT,
             typename ChannelOrderT>
      channel_severity_filter_actor< typename ChannelDescriptorT::value_type, typename SeverityDescriptorT::value_type, fallback_to_none, fallback_to_none, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_keyword< ChannelDescriptorT, ActorT > const & channel_keyword,
                              attribute_keyword< SeverityDescriptorT, ActorT > const & severity_keyword,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename SeverityT, typename ChannelT, typename ChannelFallbackT,
             typename ChannelTagT, template< typename > class ActorT,
             typename SeverityCompareT, typename ChannelOrderT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, fallback_to_none, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_name const & severity_name,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename ChannelT, typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT,
             typename SeverityCompareT, typename ChannelOrderT>
      channel_severity_filter_actor< ChannelT, SeverityT, fallback_to_none, SeverityFallbackT, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_name const & channel_name,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);
    template<typename ChannelT, typename ChannelFallbackT, typename ChannelTagT,
             typename SeverityT, typename SeverityFallbackT,
             typename SeverityTagT, template< typename > class ActorT,
             typename SeverityCompareT, typename ChannelOrderT>
      channel_severity_filter_actor< ChannelT, SeverityT, ChannelFallbackT, SeverityFallbackT, ChannelOrderT, SeverityCompareT, use_std_allocator, ActorT >
      channel_severity_filter(attribute_actor< ChannelT, ChannelFallbackT, ChannelTagT, ActorT > const & channel_placeholder,
                              attribute_actor< SeverityT, SeverityFallbackT, SeverityTagT, ActorT > const & severity_placeholder,
                              SeverityCompareT const & severity_compare,
                              ChannelOrderT const & channel_order);

## Description

The function generates a filtering predicate that checks the severity levels of log records in different channels. The predicate will return `true` if the record severity level is not less than the threshold for the channel the record belongs to.