diff --git a/fbreader/src/bookmodel/BookModel.h b/fbreader/src/bookmodel/BookModel.h
index bc110a9ed..a70a61686 100644
--- a/fbreader/src/bookmodel/BookModel.h
+++ b/fbreader/src/bookmodel/BookModel.h
@@ -55,6 +55,7 @@ class BookModel : public ZLUserDataHolder {
 	class HyperlinkMatcher {
 
 	public:
+		virtual ~HyperlinkMatcher() {}
 		virtual Label match(const std::map<std::string,Label> &lMap, const std::string &id) const = 0;
 	};
 
diff --git a/fbreader/src/formats/doc/OleStreamReader.cpp b/fbreader/src/formats/doc/OleStreamReader.cpp
index 32e49a638..f43dab261 100644
--- a/fbreader/src/formats/doc/OleStreamReader.cpp
+++ b/fbreader/src/formats/doc/OleStreamReader.cpp
@@ -26,6 +26,9 @@
 OleStreamReader::OleStreamReader() : myNextPieceNumber(0) {
 }
 
+OleStreamReader::~OleStreamReader() {
+}
+
 bool OleStreamReader::readDocument(shared_ptr<ZLInputStream> inputStream, bool doReadFormattingData) {
 	static const std::string WORD_DOCUMENT = "WordDocument";
 
diff --git a/fbreader/src/formats/doc/OleStreamReader.h b/fbreader/src/formats/doc/OleStreamReader.h
index cc1a8f6a0..21f160280 100644
--- a/fbreader/src/formats/doc/OleStreamReader.h
+++ b/fbreader/src/formats/doc/OleStreamReader.h
@@ -28,6 +28,7 @@ class OleStreamReader {
 
 public:
 	OleStreamReader();
+	virtual ~OleStreamReader();
 	bool readDocument(shared_ptr<ZLInputStream> stream, bool doReadFormattingData);
 
 protected:
diff --git a/fbreader/src/formats/txt/TxtReader.cpp b/fbreader/src/formats/txt/TxtReader.cpp
index ad6c344d9..88bcb3994 100644
--- a/fbreader/src/formats/txt/TxtReader.cpp
+++ b/fbreader/src/formats/txt/TxtReader.cpp
@@ -27,6 +27,7 @@ class TxtReaderCore {
 
 public:
 	TxtReaderCore(TxtReader &reader);
+	virtual ~TxtReaderCore();
 	virtual void readDocument(ZLInputStream &stream);
 
 protected:
@@ -90,6 +91,9 @@ void TxtReader::readDocument(ZLInputStream &stream) {
 TxtReaderCore::TxtReaderCore(TxtReader &reader) : myReader(reader) {
 }
 
+TxtReaderCore::~TxtReaderCore() {
+}
+
 TxtReaderCoreUtf16::TxtReaderCoreUtf16(TxtReader &reader) : TxtReaderCore(reader) {
 }
 
diff --git a/fbreader/src/network/BookReference.h b/fbreader/src/network/BookReference.h
index 7bc518d86..f58b0e7e0 100644
--- a/fbreader/src/network/BookReference.h
+++ b/fbreader/src/network/BookReference.h
@@ -44,6 +44,7 @@ class BookReference {
 
 public:
 	BookReference(const std::string &url, Format format, Type type);
+	virtual ~BookReference() {}
 
 public:
 	const std::string URL;
diff --git a/zlibrary/core/src/dialogs/ZLOpenFileDialog.h b/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
index a0c534500..dc074e809 100644
--- a/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
+++ b/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
@@ -35,6 +35,7 @@ class ZLOpenFileDialog {
 	};
 
 public:
+	virtual ~ZLOpenFileDialog() {}
 	virtual bool run() = 0;
 	virtual std::string filePath() const = 0;
 	virtual std::string directoryPath() const = 0;
diff --git a/zlibrary/core/src/network/ZLNetworkRequest.cpp b/zlibrary/core/src/network/ZLNetworkRequest.cpp
index 48093e7c9..6c78ad5b6 100644
--- a/zlibrary/core/src/network/ZLNetworkRequest.cpp
+++ b/zlibrary/core/src/network/ZLNetworkRequest.cpp
@@ -27,6 +27,9 @@ ZLNetworkRequest::ZLNetworkRequest(const std::string &url) :
 	ZLLogger::Instance().println("URL", url);
 }
 
+ZLNetworkRequest::~ZLNetworkRequest() {
+}
+
 const std::string &ZLNetworkRequest::errorMessage() const {
 	return myErrorMessage;
 }
diff --git a/zlibrary/core/src/network/ZLNetworkRequest.h b/zlibrary/core/src/network/ZLNetworkRequest.h
index 6397169ce..61db10165 100644
--- a/zlibrary/core/src/network/ZLNetworkRequest.h
+++ b/zlibrary/core/src/network/ZLNetworkRequest.h
@@ -49,6 +49,8 @@ class ZLNetworkRequest {
 	ZLNetworkRequest(const std::string &url);
 
 public:
+	virtual ~ZLNetworkRequest();
+
 	virtual bool handleHeader(void *ptr, std::size_t size);
 	virtual bool handleContent(void *ptr, std::size_t size) = 0;
 
diff --git a/zlibrary/core/src/resources/ZLResource.cpp b/zlibrary/core/src/resources/ZLResource.cpp
index 78963f1c7..fa5f4e36d 100644
--- a/zlibrary/core/src/resources/ZLResource.cpp
+++ b/zlibrary/core/src/resources/ZLResource.cpp
@@ -36,6 +36,7 @@ class ZLTreeResource : public ZLResource {
 private:
 	class Condition {
 	public:
+		virtual ~Condition() {}
 		virtual bool accepts(int number) = 0;
 	};
 
diff --git a/zlibrary/core/src/tree/ZLTreeListener.h b/zlibrary/core/src/tree/ZLTreeListener.h
index 3a2c20a40..564cde4a3 100644
--- a/zlibrary/core/src/tree/ZLTreeListener.h
+++ b/zlibrary/core/src/tree/ZLTreeListener.h
@@ -27,6 +27,8 @@
 class ZLTreeListener {
 
 public:
+	virtual ~ZLTreeListener() {}
+
 	virtual void onExpandRequest(ZLTreeNode *node) = 0;
 	virtual void onCloseRequest() = 0;
 	// Parent has new or remove child at index
diff --git a/zlibrary/core/src/tree/ZLTreePageNode.h b/zlibrary/core/src/tree/ZLTreePageNode.h
index fdadec214..a3c07ad8d 100644
--- a/zlibrary/core/src/tree/ZLTreePageNode.h
+++ b/zlibrary/core/src/tree/ZLTreePageNode.h
@@ -25,6 +25,7 @@
 
 class ZLTreePageInfo {
 public:
+	virtual ~ZLTreePageInfo() {}
 
 	virtual bool isPageInfoLoaded() = 0;
 	virtual void loadAll(shared_ptr<ZLNetworkRequest::Listener> listener) = 0;
diff --git a/zlibrary/core/src/tree/ZLTreeSearcher.h b/zlibrary/core/src/tree/ZLTreeSearcher.h
index 25b183185..b85e5edea 100644
--- a/zlibrary/core/src/tree/ZLTreeSearcher.h
+++ b/zlibrary/core/src/tree/ZLTreeSearcher.h
@@ -24,6 +24,7 @@
 
 class ZLTreeSearcher {
 public:
+	virtual ~ZLTreeSearcher() {}
 	virtual void simpleSearch(const std::string &pattern) = 0;
 };