use dds-adapter-watcher in dds-participant with refresh_qos()

third-party/realdds/include/realdds/dds-participant.h

@@ -39,6 +39,9 @@ class slice;
 namespace realdds {
 
 
+class dds_adapter_watcher;
+
+
 // The starting point for any DDS interaction, a participant has a name and is the focal point for creating, destroying,
 // and managing other DDS objects. It defines the DDS domain (ID) in which every other object lives.
 //
@@ -53,6 +56,7 @@ class dds_participant
     struct listener_impl;
 
     rsutils::json _settings;
+    std::shared_ptr< dds_adapter_watcher > _adapter_watcher;
 
 public:
     dds_participant() = default;
@@ -71,6 +75,12 @@ class dds_participant
         qos( std::string const & participant_name );
     };
 
+    // Return the QoS (so user won't have to actually know about the DomainParticipant)
+    eprosima::fastdds::dds::DomainParticipantQos const & get_qos() const;
+
+    // Refresh the QoS, so it will pick up any changes in the system (e.g., if adapters have changed)
+    void refresh_qos();
+
     // Creates the underlying DDS participant and sets the QoS.
     // If callbacks are needed, set them before calling init. Note they may be called before init returns!
     // 

third-party/realdds/src/dds-participant.cpp

@@ -6,6 +6,7 @@
 #include <realdds/dds-guid.h>
 #include <realdds/dds-time.h>
 #include <realdds/dds-serialization.h>
+#include <realdds/dds-adapter-watcher.h>
 
 #include <fastdds/dds/domain/DomainParticipantFactory.hpp>
 #include <fastdds/dds/domain/DomainParticipantListener.hpp>
@@ -209,6 +210,10 @@ dds_participant::qos::qos( std::string const & participant_name )
     //udp_transport->maxMessageSize = 1470; TODO this affects reading, too! We need writer-only property for this...
     transport().use_builtin_transports = false;
     transport().user_transports.push_back( udp_transport );
+
+    // If the user has many local interfaces (possible: I have 5!) then anything over the limit will not get
+    // communicated and end-point discovery will be affected. We want to avoid this so increase the limit:
+    allocation().locators.max_unicast_locators = 10;
 }
 
 
@@ -253,6 +258,13 @@ void dds_participant::init( dds_domain_id domain_id, qos & pqos, rsutils::json c
     else
         DDS_THROW( runtime_error, "provided settings are invalid: " << settings );
 
+    _adapter_watcher = std::make_shared< dds_adapter_watcher >(
+        [this]
+        {
+            LOG_DEBUG( name() << ": refreshing QoS" );
+            refresh_qos();
+        } );
+
     LOG_DEBUG( "participant " << realdds::print_raw_guid( guid() ) << " " << pqos << "\nis up on domain " << domain_id
                               << " from settings: " << std::setw( 4 ) << _settings );
 
@@ -293,17 +305,23 @@ dds_domain_id dds_participant::domain_id() const
 }
 
 
+eprosima::fastdds::dds::DomainParticipantQos const & dds_participant::get_qos() const
+{
+    return get()->get_qos();
+}
+
+
 rsutils::string::slice dds_participant::name() const
 {
-    auto & string_255 = get()->get_qos().name();
+    auto & string_255 = get_qos().name();
     return rsutils::string::slice( string_255.c_str(), string_255.size() );
 }
 
 
 std::shared_ptr< const eprosima::fastdds::rtps::FlowControllerDescriptor >
 dds_participant::find_flow_controller( char const * name ) const
 {
-    for( auto & controller : get()->get_qos().flow_controllers() )
+    for( auto & controller : get_qos().flow_controllers() )
     {
         if( ! strcmp( name, controller->name ) )
             return controller;
@@ -312,6 +330,12 @@ dds_participant::find_flow_controller( char const * name ) const
 }
 
 
+void dds_participant::refresh_qos()
+{
+    get()->set_qos( get_qos() );
+}
+
+
 std::string dds_participant::print( dds_guid const & guid_to_print ) const
 {
     return rsutils::string::from( realdds::print_guid( guid_to_print, guid() ) );