[tasklet] use function reference (instead of pointer) for tasklet handler (#5136)

src/core/coap/coap_secure.cpp

@@ -51,7 +51,7 @@ CoapSecure::CoapSecure(Instance &aInstance, bool aLayerTwoSecurity)
     , mConnectedCallback(nullptr)
     , mConnectedContext(nullptr)
     , mTransmitQueue()
-    , mTransmitTask(aInstance, &CoapSecure::HandleTransmit, this)
+    , mTransmitTask(aInstance, CoapSecure::HandleTransmit, this)
 {
 }
 

src/core/common/notifier.cpp

@@ -51,7 +51,7 @@ Notifier::Notifier(Instance &aInstance)
     : InstanceLocator(aInstance)
     , mEventsToSignal()
     , mSignaledEvents()
-    , mTask(aInstance, &Notifier::EmitEvents, this)
+    , mTask(aInstance, Notifier::EmitEvents, this)
     , mReceivers()
 {
     for (unsigned int i = 0; i < kMaxExternalHandlers; i++)

src/core/common/tasklet.hpp

@@ -67,12 +67,12 @@ class Tasklet : public InstanceLocator, public OwnerLocator
 
 public:
     /**
-     * This function pointer is called when the tasklet is run.
+     * This function reference is called when the tasklet is run.
      *
      * @param[in]  aTasklet  A reference to the tasklet being run.
      *
      */
-    typedef void (*Handler)(Tasklet &aTasklet);
+    typedef void (&Handler)(Tasklet &aTasklet);
 
     /**
      * This constructor creates a tasklet instance.

src/core/mac/mac.cpp

@@ -115,7 +115,7 @@ Mac::Mac(Instance &aInstance)
     , mActiveScanHandler(nullptr) // Initialize `mActiveScanHandler` and `mEnergyScanHandler` union
     , mScanHandlerContext(nullptr)
     , mSubMac(aInstance)
-    , mOperationTask(aInstance, &Mac::HandleOperationTask, this)
+    , mOperationTask(aInstance, Mac::HandleOperationTask, this)
     , mTimer(aInstance, Mac::HandleTimer, this)
     , mOobFrame(nullptr)
     , mKeyIdMode2FrameCounter(0)

src/core/net/ip6.cpp

@@ -57,7 +57,7 @@ Ip6::Ip6(Instance &aInstance)
     , mReceiveIp6DatagramCallback(nullptr)
     , mReceiveIp6DatagramCallbackContext(nullptr)
     , mSendQueue()
-    , mSendQueueTask(aInstance, HandleSendQueue, this)
+    , mSendQueueTask(aInstance, Ip6::HandleSendQueue, this)
     , mIcmp(aInstance)
     , mUdp(aInstance)
     , mMpl(aInstance)

src/core/thread/mesh_forwarder.cpp

@@ -66,7 +66,7 @@ MeshForwarder::MeshForwarder(Instance &aInstance)
     , mEnabled(false)
     , mTxPaused(false)
     , mSendBusy(false)
-    , mScheduleTransmissionTask(aInstance, ScheduleTransmissionTask, this)
+    , mScheduleTransmissionTask(aInstance, MeshForwarder::ScheduleTransmissionTask, this)
 #if OPENTHREAD_FTD
     , mIndirectSender(aInstance)
 #endif

src/ncp/ncp_base.cpp

@@ -205,7 +205,7 @@ NcpBase::NcpBase(Instance *aInstance)
     , mDiscoveryScanJoinerFlag(false)
     , mDiscoveryScanEnableFiltering(false)
     , mDiscoveryScanPanId(0xffff)
-    , mUpdateChangedPropsTask(*aInstance, &NcpBase::UpdateChangedProps, this)
+    , mUpdateChangedPropsTask(*aInstance, NcpBase::UpdateChangedProps, this)
     , mThreadChangedFlags(0)
     , mChangedPropsSet()
     , mHostPowerState(SPINEL_HOST_POWER_STATE_ONLINE)