simplify GUID printing

src/client.cpp

@@ -458,10 +458,8 @@ void Context::Pvt::onBeacon(const UDPManager::Beacon& msg)
         beaconSenders.emplace(msg.src, BTrack{msg.guid, now});
     }
 
-    log_debug_printf(io, "%s New server %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x %s\n",
-               msg.src.tostring().c_str(),
-               guid[0], guid[1], guid[2], guid[3], guid[4], guid[5], guid[6], guid[7], guid[8], guid[9], guid[10], guid[11],
-               msg.server.tostring().c_str());
+    log_debug_printf(io, "%s\n",
+                     std::string(SB()<<msg.src<<" New server "<<guid<<' '<<msg.server).c_str());
 
     poke(false);
 }
@@ -527,7 +525,7 @@ bool Context::Pvt::onSearch()
     }
 
     if(cmd==CMD_SEARCH_RESPONSE) {
-        std::array<uint8_t, 12> guid;
+        ServerGUID guid;
         SockAddr serv;
         uint16_t port = 0;
         uint8_t found = 0u;
@@ -787,9 +785,8 @@ void Context::Pvt::tickBeaconClean()
 
         if(age < -15.0 || age > 2.1*180.0) {
             auto& guid = cur->second.guid;
-            log_debug_printf(io, "Lost server %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x %s\n",
-                       guid[0], guid[1], guid[2], guid[3], guid[4], guid[5], guid[6], guid[7], guid[8], guid[9], guid[10], guid[11],
-                       cur->first.tostring().c_str());
+            log_debug_printf(io, "%s\n",
+                             std::string(SB()<<" Lost server "<<guid<<' '<<cur->first).c_str());
 
             beaconSenders.erase(cur);
         }

src/clientimpl.h

@@ -145,7 +145,7 @@ struct Channel {
     size_t nSearch = 0u;
 
     // GUID of last positive reply when state!=Searching
-    std::array<uint8_t, 12> guid;
+    ServerGUID guid;
     SockAddr replyAddr;
 
     std::list<std::weak_ptr<OperationBase>> pending;
@@ -192,7 +192,7 @@ struct Context::Pvt
     bool poked = false;
 
     struct BTrack {
-        std::array<uint8_t, 12> guid;
+        ServerGUID guid;
         epicsTimeStamp lastRx;
     };
     std::map<SockAddr, BTrack> beaconSenders;

src/pvxs/server.h

@@ -145,7 +145,7 @@ struct PVXS_API Config {
     bool auto_beacon = true;
 
     //! Server unique ID.  Only meaningful in readback via Server::config()
-    std::array<uint8_t, 12> guid{};
+    ServerGUID guid{};
 
     // compat
     static inline Config from_env() { return Config{}.applyEnv(); }

src/pvxs/util.h

@@ -8,6 +8,7 @@
 #define PVXS_UTIL_H
 
 #include <map>
+#include <array>
 #include <functional>
 #include <iosfwd>
 #include <type_traits>
@@ -68,6 +69,11 @@ inline detail::Escaper escape(const char* s,size_t n) {
     return detail::Escaper(s,n);
 }
 
+struct ServerGUID : public std::array<uint8_t, 12> {};
+
+PVXS_API
+std::ostream& operator<<(std::ostream&, const ServerGUID&);
+
 #if !defined(__rtems__) && !defined(vxWorks)
 
 /** Minimal portable process signal handling in CLI tools.

src/udp_collector.h

@@ -36,7 +36,7 @@ struct PVXS_API UDPManager
     struct Beacon {
         SockAddr& src;
         SockAddr server;
-        std::array<uint8_t, 12> guid;
+        ServerGUID guid;
         Beacon(SockAddr& src) :src(src) {}
     };
     //! Create subscription for Beacon messages.

src/util.cpp

@@ -253,6 +253,16 @@ std::ostream& operator<<(std::ostream& strm, const Escaper& esc)
 
 } // namespace detail
 
+std::ostream& operator<<(std::ostream& strm, const ServerGUID& guid)
+{
+    Restore R(strm);
+    strm.width(2);
+    strm<<"0x"<<std::hex<<std::setfill('0');
+    for(size_t i=0; i<guid.size(); i++)
+        strm<<std::setw(2)<<unsigned(guid[i]);
+    return strm;
+}
+
 #if !defined(__rtems__) && !defined(vxWorks)
 
 static

src/utilpvt.h

@@ -251,6 +251,25 @@ public:
 PVXS_API
 std::ostream& operator<<(std::ostream& strm, const SockAddr& addr);
 
+//! Scoped restore of std::ostream state (format flags, fill char, and field width)
+struct Restore {
+    std::ostream& strm;
+    std::ios_base::fmtflags pflags;
+    std::ostream::char_type pfill;
+    std::streamsize pwidth;
+    Restore(std::ostream& strm)
+        :strm(strm)
+        ,pflags(strm.flags())
+        ,pfill(strm.fill())
+        ,pwidth(strm.width())
+    {}
+    ~Restore() {
+        strm.flags(pflags);
+        strm.fill(pfill);
+        strm.width(pwidth);
+    }
+};
+
 template<std::atomic<size_t>* Cnt>
 struct InstCounter
 {

tools/pvxvct.cpp

@@ -232,10 +232,8 @@ int main(int argc, char *argv[])
                 return;
 
             const auto& guid = msg.guid;
-            log_info_printf(out, "%s Beacon %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x %s\n",
-                       msg.src.tostring().c_str(),
-                       guid[0], guid[1], guid[2], guid[3], guid[4], guid[5], guid[6], guid[7], guid[8], guid[9], guid[10], guid[11],
-                       msg.server.tostring().c_str());
+            log_debug_printf(out, "%s\n",
+                             std::string(pva::impl::SB()<<msg.src<<" Beacon "<<guid<<' '<<msg.server).c_str());
 
         };