/**
  * @brief Abstract class for pingers.
+ * Scope: one object per host.
  */
 class Pinger
 {
 
             const std::string &destination_ip,
             const uint16_t destination_port
     );
-    void ping_done_handler(bool ping_success);
+    void ping_done_handler( bool ping_success );
 
     void setup_next_ping();
     void schedule_next_ping();
 
     Icmpv4Header icmp_header(
             type, code, checksum, identifier, sequence_number
     );
-    IcmpPacketItem icmp_packet(new Icmpv4Packet( icmp_header, icmp_data ));
+    IcmpPacketItem icmp_packet( new Icmpv4Packet( icmp_header, icmp_data ) );
 
     return icmp_packet;
 }
     Icmpv6Header icmp_header(
             type, code, checksum, identifier, sequence_number
     );
-    IcmpPacketItem icmp_packet(new Icmpv6Packet( icmp_header, icmp_data ));
+    IcmpPacketItem icmp_packet( new Icmpv6Packet( icmp_header, icmp_data ) );
 
     return icmp_packet;
 }
 
 void IcmpPinger::ping(
         const string &destination_ip,
         const uint16_t /*destination_port*/, // the ICMP protocol does not use ports
-        function< void(bool) > ping_done_callback
+        function<void(bool)> ping_done_callback
 )
 {
     BOOST_ASSERT( !destination_ip.empty() );
 
     virtual void ping(
             const std::string &destination_ip,
             const uint16_t destination_port,
-            boost::function< void(bool) > ping_done_callback
+            boost::function<void(bool)> ping_done_callback
     );
 
 private: