osrm-backend/Server/DataStructures/SharedBarriers.h

#include <boost/interprocess/sync/named_mutex.hpp>
#include <boost/interprocess/sync/named_condition.hpp>

struct SharedBarriers {

   SharedBarriers ()
    :
      pending_update_mutex(
         boost::interprocess::open_or_create,
         "pending_update"
      ),
      update_mutex(
         boost::interprocess::open_or_create,
         "update"
      ),
      query_mutex(
         boost::interprocess::open_or_create,
         "query"
      ),
      no_running_queries_condition(
         boost::interprocess::open_or_create,
         "no_running_queries"
      ),
      update_ongoing(false),
      number_of_queries(0)
   { }

   // Mutex to protect access to the boolean variable
   boost::interprocess::named_mutex   pending_update_mutex;
   boost::interprocess::named_mutex   update_mutex;
   boost::interprocess::named_mutex   query_mutex;

   // Condition that no update is running
   boost::interprocess::named_condition  no_running_queries_condition;

   // Is there an ongoing update?
   bool update_ongoing;
   // Is there any query?
   int number_of_queries;
};