clang-tidy fixes part-3 / 4, adding Check `performance-*`

See also jaulib commit 9160f9a4b74f5e5ae07f715025ea4d3aafdf6ab3

Details:
- Using 'const T&' as method argument type where applicable, i.e. not when required to pass value off-thread.
  - Notable: Can also hold a default value!

- Using `const T&` in range-loop where applicable

- Drop std::move for trivial types

- ...

18 files changed, 80 insertions, 75 deletions

diff --git a/api/direct_bt/ATTPDUTypes.hpp b/api/direct_bt/ATTPDUTypes.hpp
index 1c7e36ed..b684e984 100644
--- a/api/direct_bt/ATTPDUTypes.hpp
+++ b/api/direct_bt/ATTPDUTypes.hpp
@@ -204,23 +204,23 @@ namespace direct_bt {
 
     class AttException : public jau::RuntimeException {
         protected:
-            AttException(std::string const type, std::string const m, const char* file, int line) noexcept
-            : RuntimeException(type, m, file, line) {}
+            AttException(std::string type, std::string const& m, const char* file, int line) noexcept
+            : RuntimeException(std::move(type), m, file, line) {}
 
         public:
-            AttException(std::string const m, const char* file, int line) noexcept
+            AttException(std::string const& m, const char* file, int line) noexcept
             : RuntimeException("AttException", m, file, line) {}
     };
 
     class AttOpcodeException : public AttException {
         public:
-            AttOpcodeException(std::string const m, const char* file, int line) noexcept
+            AttOpcodeException(std::string const& m, const char* file, int line) noexcept
             : AttException("AttOpcodeException", m, file, line) {}
     };
 
     class AttValueException : public AttException {
         public:
-            AttValueException(std::string const m, const char* file, int line) noexcept
+            AttValueException(std::string const& m, const char* file, int line) noexcept
             : AttException("AttValueException", m, file, line) {}
     };
 
diff --git a/api/direct_bt/BTAdapter.hpp b/api/direct_bt/BTAdapter.hpp
index 5915241b..b8613626 100644
--- a/api/direct_bt/BTAdapter.hpp
+++ b/api/direct_bt/BTAdapter.hpp
@@ -472,10 +472,10 @@ namespace direct_bt {
                                                       uint16_t latency, uint16_t supervision_timeout) noexcept;
             friend HCIStatusCode BTDevice::connectBREDR(const uint16_t pkt_type, const uint16_t clock_offset, const uint8_t role_switch) noexcept;
             friend void BTDevice::processL2CAPSetup(BTDeviceRef sthis);
-            friend bool BTDevice::updatePairingState(BTDeviceRef sthis, const MgmtEvent& evt, const HCIStatusCode evtStatus, SMPPairingState claimed_state) noexcept;
-            friend void BTDevice::hciSMPMsgCallback(BTDeviceRef sthis, const SMPPDUMsg& msg, const HCIACLData::l2cap_frame& source) noexcept;
+            friend bool BTDevice::updatePairingState(const BTDeviceRef& sthis, const MgmtEvent& evt, const HCIStatusCode evtStatus, SMPPairingState claimed_state) noexcept;
+            friend void BTDevice::hciSMPMsgCallback(const BTDeviceRef& sthis, const SMPPDUMsg& msg, const HCIACLData::l2cap_frame& source) noexcept;
             friend void BTDevice::processDeviceReady(BTDeviceRef sthis, const uint64_t timestamp);
-            friend bool BTDevice::connectGATT(std::shared_ptr<BTDevice> sthis) noexcept;
+            friend bool BTDevice::connectGATT(const std::shared_ptr<BTDevice>& sthis) noexcept;
             friend jau::darray<BTGattServiceRef> BTDevice::getGattServices() noexcept;
 
             bool lockConnect(const BTDevice & device, const bool wait, const SMPIOCapability io_cap) noexcept;
@@ -502,7 +502,7 @@ namespace direct_bt {
             void removeSharedDevice(const BTDevice & device) noexcept;
 
             static SMPKeyBinRef findSMPKeyBin(key_list_t & keys, BDAddressAndType const & remoteAddress) noexcept;
-            static bool removeSMPKeyBin(key_list_t & keys, BDAddressAndType const & remoteAddress, const bool remove_file, const std::string key_path_) noexcept;
+            static bool removeSMPKeyBin(key_list_t & keys, BDAddressAndType const & remoteAddress, const bool remove_file, const std::string& key_path_) noexcept;
             SMPKeyBinRef findSMPKeyBin(BDAddressAndType const & remoteAddress) noexcept;
             /** Adding a SMPKeyBin will remove previous entry. */
             bool addSMPKeyBin(const SMPKeyBinRef& key, const bool write_file) noexcept;
@@ -516,7 +516,7 @@ namespace direct_bt {
             void l2capServerWork(jau::service_runner& sr) noexcept;
             void l2capServerInit(jau::service_runner& sr) noexcept;
             void l2capServerEnd(jau::service_runner& sr) noexcept;
-            std::unique_ptr<L2CAPClient> get_l2cap_connection(std::shared_ptr<BTDevice> device);
+            std::unique_ptr<L2CAPClient> get_l2cap_connection(const std::shared_ptr<BTDevice>& device);
 
             void mgmtEvNewSettingsMgmt(const MgmtEvent& e) noexcept;
             void updateAdapterSettings(const bool off_thread, const AdapterSetting new_settings, const bool sendEvent, const uint64_t timestamp) noexcept;
@@ -558,8 +558,8 @@ namespace direct_bt {
 
             void hciSMPMsgCallback(const BDAddressAndType & addressAndType,
                                    const SMPPDUMsg& msg, const HCIACLData::l2cap_frame& source) noexcept;
-            void sendDevicePairingState(BTDeviceRef device, const SMPPairingState state, const PairingMode mode, uint64_t timestamp) noexcept;
-            void notifyPairingStageDone(BTDeviceRef device, uint64_t timestamp) noexcept;
+            void sendDevicePairingState(const BTDeviceRef& device, const SMPPairingState state, const PairingMode mode, uint64_t timestamp) noexcept;
+            void notifyPairingStageDone(const BTDeviceRef& device, uint64_t timestamp) noexcept;
             void sendDeviceReady(BTDeviceRef device, uint64_t timestamp) noexcept;
 
             jau::service_runner discovery_service;
@@ -1208,7 +1208,7 @@ namespace direct_bt {
              * @see DBGattServer::setServicesHandles()
              * @since 2.5.3
              */
-            HCIStatusCode startAdvertising(DBGattServerRef gattServerData_,
+            HCIStatusCode startAdvertising(const DBGattServerRef& gattServerData_,
                                            EInfoReport& eir,
                                            EIRDataType adv_mask = EIRDataType::FLAGS | EIRDataType::SERVICE_UUID,
                                            EIRDataType scanrsp_mask = EIRDataType::NAME | EIRDataType::CONN_IVAL,
@@ -1260,7 +1260,7 @@ namespace direct_bt {
              * @see DBGattServer::setServicesHandles()
              * @since 2.4.0
              */
-            HCIStatusCode startAdvertising(DBGattServerRef gattServerData_,
+            HCIStatusCode startAdvertising(const DBGattServerRef& gattServerData_,
                                            const uint16_t adv_interval_min=160, const uint16_t adv_interval_max=480,
                                            const AD_PDU_Type adv_type=AD_PDU_Type::ADV_IND,
                                            const uint8_t adv_chan_map=0x07,
diff --git a/api/direct_bt/BTAddress.hpp b/api/direct_bt/BTAddress.hpp
index 6fa7b0b2..29530adf 100644
--- a/api/direct_bt/BTAddress.hpp
+++ b/api/direct_bt/BTAddress.hpp
@@ -196,8 +196,8 @@ namespace direct_bt {
             constexpr BDAddressAndType() noexcept : address(), type{BDAddressType::BDADDR_UNDEFINED} { }
             BDAddressAndType(const BDAddressAndType &o) noexcept : address(o.address), type(o.type) { }
             BDAddressAndType(BDAddressAndType &&o) noexcept {
-                address = std::move(o.address);
-                type = std::move(o.type);
+                address = o.address;
+                type = o.type;
             }
             constexpr BDAddressAndType& operator=(const BDAddressAndType &o) noexcept {
                 address = o.address;
@@ -205,8 +205,8 @@ namespace direct_bt {
                 return *this;
             }
             BDAddressAndType& operator=(BDAddressAndType &&o) noexcept {
-                address = std::move(o.address);
-                type = std::move(o.type);
+                address = o.address;
+                type = o.type;
                 return *this;
             }
 
diff --git a/api/direct_bt/BTDevice.hpp b/api/direct_bt/BTDevice.hpp
index d4c7ba7e..e4528c4c 100644
--- a/api/direct_bt/BTDevice.hpp
+++ b/api/direct_bt/BTDevice.hpp
@@ -170,8 +170,8 @@ namespace direct_bt {
             EIRDataType update(GattGenericAccessSvc const &data, const uint64_t timestamp) noexcept;
 
             void notifyDisconnected() noexcept;
-            void notifyConnected(std::shared_ptr<BTDevice> sthis, const uint16_t handle, const SMPIOCapability io_cap) noexcept;
-            void notifyLEFeatures(std::shared_ptr<BTDevice> sthis, const LE_Features features) noexcept;
+            void notifyConnected(const std::shared_ptr<BTDevice>& sthis, const uint16_t handle, const SMPIOCapability io_cap) noexcept;
+            void notifyLEFeatures(const std::shared_ptr<BTDevice>& sthis, const LE_Features features) noexcept;
             void notifyLEPhyUpdateComplete(const HCIStatusCode status, const LE_PHYs Tx, const LE_PHYs Rx) noexcept;
 
             /**
@@ -203,7 +203,7 @@ namespace direct_bt {
 
             bool checkPairingKeyDistributionComplete() const noexcept;
 
-            bool updatePairingState(std::shared_ptr<BTDevice> sthis, const MgmtEvent& evt, const HCIStatusCode evtStatus, SMPPairingState claimed_state) noexcept;
+            bool updatePairingState(const std::shared_ptr<BTDevice>& sthis, const MgmtEvent& evt, const HCIStatusCode evtStatus, SMPPairingState claimed_state) noexcept;
 
             /**
              * Forwarded from HCIHandler -> BTAdapter -> this BTDevice
@@ -211,7 +211,7 @@ namespace direct_bt {
              * Will be initiated by processL2CAPSetup()'s security_level setup after connectLE(..), i.e. notifyConnected() and notifyLEFeatures().
              * </p>
              */
-            void hciSMPMsgCallback(std::shared_ptr<BTDevice> sthis, const SMPPDUMsg& msg, const HCIACLData::l2cap_frame& source) noexcept;
+            void hciSMPMsgCallback(const std::shared_ptr<BTDevice>& sthis, const SMPPDUMsg& msg, const HCIACLData::l2cap_frame& source) noexcept;
 
             /**
              * Setup GATT via connectGATT() off-thread.
@@ -232,7 +232,7 @@ namespace direct_bt {
              * The GATTHandler is managed by this device instance and closed via disconnectGATT().
              * </p>
              */
-            bool connectGATT(std::shared_ptr<BTDevice> sthis) noexcept;
+            bool connectGATT(const std::shared_ptr<BTDevice>& sthis) noexcept;
 
             /**
              * Will be performed within disconnect() and notifyDisconnected().
diff --git a/api/direct_bt/BTDeviceRegistry.hpp b/api/direct_bt/BTDeviceRegistry.hpp
index 8112d2a7..7f56a68e 100644
--- a/api/direct_bt/BTDeviceRegistry.hpp
+++ b/api/direct_bt/BTDeviceRegistry.hpp
@@ -61,7 +61,7 @@ namespace direct_bt {
             EUI48Sub addressSub;
             std::string nameSub;
 
-            DeviceQuery(EUI48Sub as) : type(Type::EUI48SUB), addressSub(std::move(as)), nameSub() {}
+            DeviceQuery(const EUI48Sub& as) : type(Type::EUI48SUB), addressSub(as), nameSub() {}
 
             DeviceQuery(std::string ns) : type(Type::NAME), addressSub(EUI48Sub::ANY_DEVICE), nameSub(std::move(ns)) {}
 
diff --git a/api/direct_bt/BTGattHandler.hpp b/api/direct_bt/BTGattHandler.hpp
index 8b42f5bb..d19c1b31 100644
--- a/api/direct_bt/BTGattHandler.hpp
+++ b/api/direct_bt/BTGattHandler.hpp
@@ -496,7 +496,7 @@ namespace direct_bt {
             DBGattServerRef gattServerData;
             /** Always set, never nullptr */
             std::unique_ptr<GattServerHandler> gattServerHandler;
-            static std::unique_ptr<GattServerHandler> selectGattServerHandler(BTGattHandler& gh, DBGattServerRef gattServerData) noexcept;
+            static std::unique_ptr<GattServerHandler> selectGattServerHandler(BTGattHandler& gh, const DBGattServerRef& gattServerData) noexcept;
 
             GattServiceList_t services;
             std::shared_ptr<GattGenericAccessSvc> genericAccess = nullptr;
@@ -538,7 +538,7 @@ namespace direct_bt {
              * @see initClientGatt()
              * @see discoverCompletePrimaryServices()
              */
-            bool discoverPrimaryServices(std::shared_ptr<BTGattHandler> shared_this, GattServiceList_t& result) noexcept;
+            bool discoverPrimaryServices(const std::shared_ptr<BTGattHandler>& shared_this, GattServiceList_t& result) noexcept;
 
             /**
              * Discover all characteristics of a service and declaration attributes _only_.
@@ -575,7 +575,7 @@ namespace direct_bt {
              * @return true if successful, otherwise false
              * @see initClientGatt()
              */
-            bool discoverCompletePrimaryServices(std::shared_ptr<BTGattHandler> shared_this) noexcept;
+            bool discoverCompletePrimaryServices(const std::shared_ptr<BTGattHandler>& shared_this) noexcept;
 
         public:
             /**
@@ -639,7 +639,7 @@ namespace direct_bt {
              * Returns nullptr if not found.
              * </p>
              */
-            BTGattCharRef findCharacterisicsByValueHandle(const BTGattServiceRef service, const uint16_t charValueHandle) noexcept;
+            BTGattCharRef findCharacterisicsByValueHandle(const BTGattServiceRef& service, const uint16_t charValueHandle) noexcept;
 
             /**
              * Initialize the connection and internal data set for GATT client operations:
@@ -655,7 +655,7 @@ namespace direct_bt {
              * @see clientMTUExchange()
              * @see discoverCompletePrimaryServices()
              */
-            bool initClientGatt(std::shared_ptr<BTGattHandler> shared_this, bool& already_init) noexcept;
+            bool initClientGatt(const std::shared_ptr<BTGattHandler>& shared_this, bool& already_init) noexcept;
 
             /**
              * Returns a reference of the internal kept BTGattService list.
diff --git a/api/direct_bt/BTManager.hpp b/api/direct_bt/BTManager.hpp
index b206e4c0..e683f821 100644
--- a/api/direct_bt/BTManager.hpp
+++ b/api/direct_bt/BTManager.hpp
@@ -208,6 +208,8 @@ namespace direct_bt {
                 ClientMaxMTU = 512
             };
 
+            typedef jau::nsize_t size_type;
+            
         private:
             friend BTAdapter;
 
@@ -244,7 +246,6 @@ namespace direct_bt {
 
             ChangedAdapterSetCallbackList mgmtChangedAdapterSetCallbackList;
 
-            typedef jau::nsize_t size_type;
             typedef jau::cow_darray<std::shared_ptr<BTAdapter>, size_type> adapters_t;
             adapters_t adapters;
 
diff --git a/api/direct_bt/BTSecurityRegistry.hpp b/api/direct_bt/BTSecurityRegistry.hpp
index 124263ca..12375ac0 100644
--- a/api/direct_bt/BTSecurityRegistry.hpp
+++ b/api/direct_bt/BTSecurityRegistry.hpp
@@ -60,10 +60,10 @@ namespace direct_bt {
             SMPIOCapability io_cap_auto { SMPIOCapability::UNSET };
             int passkey = NO_PASSKEY;
 
-            Entry(EUI48Sub addrSub_)
-            : addrSub(std::move(addrSub_)), nameSub() {}
+            Entry(const EUI48Sub& addrSub_)
+            : addrSub(addrSub_), nameSub() {}
 
-            Entry(std::string  nameSub_)
+            Entry(std::string nameSub_)
             : addrSub(EUI48Sub::ALL_DEVICE), nameSub(std::move(nameSub_)) {}
 
             constexpr bool isSecLevelOrIOCapSet() const noexcept {
diff --git a/api/direct_bt/BTTypes0.hpp b/api/direct_bt/BTTypes0.hpp
index 1e6374c2..e82c6fda 100644
--- a/api/direct_bt/BTTypes0.hpp
+++ b/api/direct_bt/BTTypes0.hpp
@@ -52,7 +52,7 @@ namespace direct_bt {
 
     class BTException : public jau::RuntimeException {
         public:
-        BTException(std::string const m, const char* file, int line) noexcept
+        BTException(std::string const& m, const char* file, int line) noexcept
         : RuntimeException("BTException", m, file, line) {}
 
         BTException(const char *m, const char* file, int line) noexcept
diff --git a/api/direct_bt/BTTypes1.hpp b/api/direct_bt/BTTypes1.hpp
index a078e39d..a47eba30 100644
--- a/api/direct_bt/BTTypes1.hpp
+++ b/api/direct_bt/BTTypes1.hpp
@@ -117,8 +117,8 @@ namespace direct_bt {
             std::string short_name;
 
         protected:
-            void setName(const std::string v) noexcept { name = v; }
-            void setShortName(const std::string v) noexcept { short_name = v; }
+            void setName(std::string v) noexcept { name = std::move(v); }
+            void setShortName(std::string v) noexcept { short_name = std::move(v); }
 
         public:
             NameAndShortName() noexcept
@@ -247,10 +247,10 @@ namespace direct_bt {
                 return *this;
             }
             AdapterInfo(AdapterInfo&& o) noexcept
-            : dev_id(std::move(o.dev_id)), addressAndType(std::move(o.addressAndType)), version(std::move(o.version)),
-              manufacturer(std::move(o.manufacturer)),
-              supported_setting(std::move(o.supported_setting)),
-              current_setting(o.current_setting.load()), dev_class(std::move(o.dev_class)),
+            : dev_id(o.dev_id), addressAndType(o.addressAndType), version(o.version),
+              manufacturer(o.manufacturer),
+              supported_setting(o.supported_setting),
+              current_setting(o.current_setting.load()), dev_class(o.dev_class),
               name(std::move(o.name)), short_name(std::move(o.short_name))
             { }
             AdapterInfo& operator=(AdapterInfo &&o) noexcept = delete;
@@ -270,8 +270,8 @@ namespace direct_bt {
                 current_setting = current_setting_;
             }
             void setDevClass(const uint32_t v) noexcept { dev_class = v; }
-            void setName(const std::string v) noexcept { name = v; }
-            void setShortName(const std::string v) noexcept { short_name = v; }
+            void setName(std::string v) noexcept { name = std::move(v); }
+            void setShortName(std::string v) noexcept { short_name = std::move(v); }
 
             constexpr const AdapterSetting& get_supportedSetting() const noexcept { return supported_setting; }
 
diff --git a/api/direct_bt/DBGattServer.hpp b/api/direct_bt/DBGattServer.hpp
index 0e56f32a..36463e88 100644
--- a/api/direct_bt/DBGattServer.hpp
+++ b/api/direct_bt/DBGattServer.hpp
@@ -192,9 +192,9 @@ namespace direct_bt {
              * @param o POctet source to be taken over
              */
             DBGattDesc(DBGattDesc &&o) noexcept
-            : handle(std::move(o.handle)), type(std::move(o.type)),
+            : handle(o.handle), type(std::move(o.type)),
               value(std::move(o.value)),
-              variable_length(std::move(o.variable_length))
+              variable_length(o.variable_length)
             {
                 JAU_TRACE_DBGATT_PRINT("DBGattDesc ctor-move0: %p -> %p", &o, this);
             }
@@ -426,14 +426,14 @@ namespace direct_bt {
              * @param o POctet source to be taken over
              */
             DBGattChar(DBGattChar &&o) noexcept
-            : handle(std::move(o.handle)), end_handle(std::move(o.end_handle)),
-              value_handle(std::move(o.value_handle)), value_type(std::move(o.value_type)),
-              properties(std::move(o.properties)),
+            : handle(o.handle), end_handle(o.end_handle),
+              value_handle(o.value_handle), value_type(std::move(o.value_type)),
+              properties(o.properties),
               descriptors(std::move(o.descriptors)),
               value(std::move(o.value)),
-              variable_length(std::move(o.variable_length)),
-              clientCharConfigIndex(std::move(o.clientCharConfigIndex)),
-              userDescriptionIndex(std::move(o.userDescriptionIndex))
+              variable_length(o.variable_length),
+              clientCharConfigIndex(o.clientCharConfigIndex),
+              userDescriptionIndex(o.userDescriptionIndex)
             {
                 JAU_TRACE_DBGATT_PRINT("DBGattChar: ctor-move0: %p -> %p", &o, this);
             }
@@ -976,8 +976,8 @@ namespace direct_bt {
                 return c;
             }
 
-            bool addListener(ListenerRef l);
-            bool removeListener(ListenerRef l);
+            bool addListener(const ListenerRef& l);
+            bool removeListener(const ListenerRef& l);
             ListenerList_t& listener() { return listenerList; }
 
             std::string toFullString() {
diff --git a/api/direct_bt/HCIComm.hpp b/api/direct_bt/HCIComm.hpp
index 6eb8d97c..d762efab 100644
--- a/api/direct_bt/HCIComm.hpp
+++ b/api/direct_bt/HCIComm.hpp
@@ -91,7 +91,7 @@ namespace direct_bt {
             bool is_open() const noexcept { return 0 <= socket_descriptor; }
 
             /** The external `is interrupted` callback is used until close(), thereafter it is removed. */
-            void set_interrupted_query(get_boolean_callback_t is_interrupted_cb) { is_interrupted_extern = is_interrupted_cb; }
+            void set_interrupted_query(get_boolean_callback_t is_interrupted_cb) { is_interrupted_extern = std::move(is_interrupted_cb); }
 
             /** Returns true if interrupted by internal or external cause, hence shall stop connecting and reading. */
             bool interrupted() const noexcept { return interrupted_intern || ( !is_interrupted_extern.is_null() && is_interrupted_extern(0/*dummy*/) ); }
diff --git a/api/direct_bt/HCIHandler.hpp b/api/direct_bt/HCIHandler.hpp
index 51a66d35..e2521aad 100644
--- a/api/direct_bt/HCIHandler.hpp
+++ b/api/direct_bt/HCIHandler.hpp
@@ -316,7 +316,7 @@ namespace direct_bt {
             }
 
             HCIConnectionRef findTrackerConnection(const uint16_t handle) noexcept;
-            HCIConnectionRef removeTrackerConnection(const HCIConnectionRef conn) noexcept;
+            HCIConnectionRef removeTrackerConnection(const HCIConnectionRef& conn) noexcept;
             size_type countPendingTrackerConnections() noexcept;
             size_type getTrackerConnectionCount() noexcept;
 
@@ -485,7 +485,7 @@ namespace direct_bt {
              *
              * @return HCIStatusCode
              */
-            HCIStatusCode resetAdapter(PostShutdownFunc user_post_shutdown);
+            HCIStatusCode resetAdapter(const PostShutdownFunc& user_post_shutdown);
 
             /**
              * HCI Reset Command
diff --git a/api/direct_bt/HCITypes.hpp b/api/direct_bt/HCITypes.hpp
index b460a177..52eb936e 100644
--- a/api/direct_bt/HCITypes.hpp
+++ b/api/direct_bt/HCITypes.hpp
@@ -59,22 +59,22 @@ namespace direct_bt {
 
     class HCIException : public jau::RuntimeException {
         protected:
-            HCIException(std::string const type, std::string const m, const char* file, int line) noexcept
-            : RuntimeException(type, m, file, line) {}
+            HCIException(std::string type, std::string const& m, const char* file, int line) noexcept
+            : RuntimeException(std::move(type), m, file, line) {}
 
         public:
-            HCIException(std::string const m, const char* file, int line) noexcept
+            HCIException(std::string const& m, const char* file, int line) noexcept
             : RuntimeException("HCIException", m, file, line) {}
     };
 
     class HCIPacketException : public HCIException {
         public:
-            HCIPacketException(std::string const m, const char* file, int line) noexcept
+            HCIPacketException(std::string const& m, const char* file, int line) noexcept
             : HCIException("HCIPacketException", m, file, line) {}
     };
     class HCIOpcodeException : public HCIException {
         public:
-            HCIOpcodeException(std::string const m, const char* file, int line) noexcept
+            HCIOpcodeException(std::string const& m, const char* file, int line) noexcept
             : HCIException("HCIOpcodeException", m, file, line) {}
     };
 
diff --git a/api/direct_bt/L2CAPComm.hpp b/api/direct_bt/L2CAPComm.hpp
index 2502042e..a0f3576d 100644
--- a/api/direct_bt/L2CAPComm.hpp
+++ b/api/direct_bt/L2CAPComm.hpp
@@ -173,7 +173,7 @@ namespace direct_bt {
             bool is_open() const noexcept { return is_open_; }
 
             /** The external `is interrupted` callback is used until close(), thereafter it is removed. */
-            void set_interrupted_query(get_boolean_callback_t is_interrupted_cb) noexcept { is_interrupted_extern = is_interrupted_cb; }
+            void set_interrupted_query(get_boolean_callback_t is_interrupted_cb) noexcept { is_interrupted_extern = std::move(is_interrupted_cb); }
 
             /** Returns true if interrupted by internal or external cause, hence shall stop connecting and reading. */
             bool interrupted() const noexcept { return interrupted_int() || interrupted_ext(); }
diff --git a/api/direct_bt/MgmtTypes.hpp b/api/direct_bt/MgmtTypes.hpp
index 45654301..9a49841a 100644
--- a/api/direct_bt/MgmtTypes.hpp
+++ b/api/direct_bt/MgmtTypes.hpp
@@ -55,17 +55,17 @@ namespace direct_bt {
 
     class MgmtException : public jau::RuntimeException {
         protected:
-            MgmtException(std::string const type, std::string const m, const char* file, int line) noexcept
-            : RuntimeException(type, m, file, line) {}
+            MgmtException(std::string type, std::string const& m, const char* file, int line) noexcept
+            : RuntimeException(std::move(type), m, file, line) {}
 
         public:
-            MgmtException(std::string const m, const char* file, int line) noexcept
+            MgmtException(std::string const& m, const char* file, int line) noexcept
             : RuntimeException("MgmtException", m, file, line) {}
     };
 
     class MgmtOpcodeException : public MgmtException {
         public:
-            MgmtOpcodeException(std::string const m, const char* file, int line) noexcept
+            MgmtOpcodeException(std::string const& m, const char* file, int line) noexcept
             : MgmtException("MgmtOpcodeException", m, file, line) {}
     };
 
diff --git a/api/direct_bt/SMPTypes.hpp b/api/direct_bt/SMPTypes.hpp
index 767ebe62..af22976d 100644
--- a/api/direct_bt/SMPTypes.hpp
+++ b/api/direct_bt/SMPTypes.hpp
@@ -57,28 +57,28 @@ namespace direct_bt {
 
     class SMPException : public jau::RuntimeException {
         protected:
-            SMPException(std::string const type, std::string const m, const char* file, int line) noexcept
-            : RuntimeException(type, m, file, line) {}
+            SMPException(std::string type, std::string const& m, const char* file, int line) noexcept
+            : RuntimeException(std::move(type), m, file, line) {}
 
         public:
-            SMPException(std::string const m, const char* file, int line) noexcept
+            SMPException(std::string const& m, const char* file, int line) noexcept
             : RuntimeException("HCIException", m, file, line) {}
     };
 
     class SMPPacketException : public SMPException {
         public:
-            SMPPacketException(std::string const m, const char* file, int line) noexcept
+            SMPPacketException(std::string const& m, const char* file, int line) noexcept
             : SMPException("SMPPacketException", m, file, line) {}
     };
     class SMPOpcodeException : public SMPException {
         public:
-            SMPOpcodeException(std::string const m, const char* file, int line) noexcept
+            SMPOpcodeException(std::string const& m, const char* file, int line) noexcept
             : SMPException("SMPOpcodeException", m, file, line) {}
     };
 
     class SMPValueException : public SMPException {
         public:
-            SMPValueException(std::string const m, const char* file, int line) noexcept
+            SMPValueException(std::string const& m, const char* file, int line) noexcept
             : SMPException("SMPValueException", m, file, line) {}
     };
 
diff --git a/api/direct_bt/ieee11073/DataTypes.hpp b/api/direct_bt/ieee11073/DataTypes.hpp
index a64acf4e..e976cfe9 100644
--- a/api/direct_bt/ieee11073/DataTypes.hpp
+++ b/api/direct_bt/ieee11073/DataTypes.hpp
@@ -50,13 +50,17 @@ namespace ieee11073 {
 
     class RuntimeException : public std::exception {
       protected:
-        RuntimeException(std::string const type, std::string const m, const char* file, int line) noexcept
-        : msg(std::string(type).append(" @ ").append(file).append(":").append(std::to_string(line)).append(": ").append(m)) { }
+        std::string msg;
+        
+        RuntimeException(std::string type, std::string const& m, const char* file, int line) noexcept
+        : msg( std::move(type) ) 
+        { 
+            msg.append(" @ ").append(file).append(":").append(std::to_string(line)).append(": ").append(m);
+        }
 
       public:
-        const std::string msg;
 
-        RuntimeException(std::string const m, const char* file, int line) noexcept
+        RuntimeException(std::string const& m, const char* file, int line) noexcept
         : RuntimeException("RuntimeException", m, file, line) {}
 
         ~RuntimeException() noexcept override = default;