diff --git a/src/conference/participant.h b/src/conference/participant.h
index 7b092bb7f..dea93ed98 100644
--- a/src/conference/participant.h
+++ b/src/conference/participant.h
@@ -45,8 +45,8 @@ class Participant : public Object {
 	friend class RemoteConference;
 
 public:
-	Participant (const Address &address);
-	Participant (Address &&address);
+	explicit Participant (const Address &address);
+	explicit Participant (Address &&address);
 
 	const Address& getAddress () const;
 
diff --git a/src/db/abstract/abstract-db-p.h b/src/db/abstract/abstract-db-p.h
index 852805d39..2348ca74f 100644
--- a/src/db/abstract/abstract-db-p.h
+++ b/src/db/abstract/abstract-db-p.h
@@ -30,6 +30,8 @@ LINPHONE_BEGIN_NAMESPACE
 
 class AbstractDbPrivate : public ObjectPrivate {
 public:
+	AbstractDbPrivate () = default;
+
 	DbSession dbSession;
 
 private:
diff --git a/src/db/provider/db-session.h b/src/db/provider/db-session.h
index aed758c2a..5cfd61e05 100644
--- a/src/db/provider/db-session.h
+++ b/src/db/provider/db-session.h
@@ -43,7 +43,7 @@ public:
 		Soci
 	};
 
-	DbSession (Type type = None);
+	explicit DbSession (Type type = None);
 	DbSession (const DbSession &src);
 
 	DbSession &operator= (const DbSession &src);
diff --git a/src/nat/ice-agent.h b/src/nat/ice-agent.h
index 98101488d..42c293312 100644
--- a/src/nat/ice-agent.h
+++ b/src/nat/ice-agent.h
@@ -39,7 +39,7 @@ LINPHONE_BEGIN_NAMESPACE
 
 class IceAgent {
 public:
-	IceAgent (MediaSession &mediaSession) : mediaSession(mediaSession) {}
+	explicit IceAgent (MediaSession &mediaSession) : mediaSession(mediaSession) {}
 
 	bool candidatesGathered () const;
 	void checkSession (IceRole role, bool isReinvite);
diff --git a/src/utils/payload-type-handler.h b/src/utils/payload-type-handler.h
index d52e849fa..f5e284fda 100644
--- a/src/utils/payload-type-handler.h
+++ b/src/utils/payload-type-handler.h
@@ -42,7 +42,7 @@ struct VbrCodecBitrate {
 
 class PayloadTypeHandler {
 public:
-	PayloadTypeHandler (LinphoneCore *core) : core(core) {}
+	explicit PayloadTypeHandler (LinphoneCore *core) : core(core) {}
 
 	bctbx_list_t *makeCodecsList (SalStreamType type, int bandwidthLimit, int maxCodecs, const bctbx_list_t *previousList);