diff --git a/fbreader/fbreader/fbreader/src/bookmodel/BookModel.h b/fbreader/fbreader/fbreader/src/bookmodel/BookModel.h
index 5b2e269..ea97880 100644
--- a/fbreader/fbreader/fbreader/src/bookmodel/BookModel.h
+++ b/fbreader/fbreader/fbreader/src/bookmodel/BookModel.h
@@ -55,6 +55,7 @@ public:
 	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/fbreader/fbreader/src/database/booksdb/BooksDB.cpp b/fbreader/fbreader/fbreader/src/database/booksdb/BooksDB.cpp
index e33a22e..1b60928 100644
--- a/fbreader/fbreader/fbreader/src/database/booksdb/BooksDB.cpp
+++ b/fbreader/fbreader/fbreader/src/database/booksdb/BooksDB.cpp
@@ -145,7 +145,7 @@ shared_ptr<Book> BooksDB::loadBook(const std::string &fileName) {
 
 	myFindFileId->setFileName(fileName);
 	if (!myFindFileId->run()) {
-		return false;
+		return 0;
 	}
 	((DBIntValue&)*myLoadBook->parameter("@file_id").value()) = myFindFileId->fileId();
 	shared_ptr<DBDataReader> reader = myLoadBook->executeReader();
diff --git a/fbreader/fbreader/fbreader/src/formats/txt/PlainTextFormat.cpp b/fbreader/fbreader/fbreader/src/formats/txt/PlainTextFormat.cpp
index 76a6b62..c336bd3 100644
--- a/fbreader/fbreader/fbreader/src/formats/txt/PlainTextFormat.cpp
+++ b/fbreader/fbreader/fbreader/src/formats/txt/PlainTextFormat.cpp
@@ -95,7 +95,6 @@ void PlainTextFormatDetector::detect(ZLInputStream &stream, PlainTextFormat &for
 	
 	char *buffer = new char[BUFFER_SIZE];
 	int length;
-	char previous = 0;
 	do {
 		length = stream.read(buffer, BUFFER_SIZE);
 		const char *end = buffer + length;
@@ -135,7 +134,6 @@ void PlainTextFormatDetector::detect(ZLInputStream &stream, PlainTextFormat &for
 			} else {
 				currentLineIsEmpty = false;
 			}
-			previous = *ptr;
 		}
 	} while (length == BUFFER_SIZE);
 	delete[] buffer;
diff --git a/fbreader/fbreader/fbreader/src/network/BookReference.h b/fbreader/fbreader/fbreader/src/network/BookReference.h
index ec4e40d..1af3106 100644
--- a/fbreader/fbreader/fbreader/src/network/BookReference.h
+++ b/fbreader/fbreader/fbreader/src/network/BookReference.h
@@ -44,6 +44,7 @@ public:
 
 public:
 	BookReference(const std::string &url, Format format, Type type);
+	virtual ~BookReference() {}
 
 public:
 	const std::string URL;
diff --git a/fbreader/fbreader/zlibrary/core/src/application/ZLApplication.h b/fbreader/fbreader/zlibrary/core/src/application/ZLApplication.h
index eb83cdf..ffd9b61 100644
--- a/fbreader/fbreader/zlibrary/core/src/application/ZLApplication.h
+++ b/fbreader/fbreader/zlibrary/core/src/application/ZLApplication.h
@@ -45,7 +45,7 @@ class ZLApplicationBase {
 
 protected:
 	ZLApplicationBase(const std::string &name);
-	~ZLApplicationBase();
+	virtual ~ZLApplicationBase();
 };
 
 class ZLApplication : public ZLApplicationBase {
diff --git a/fbreader/fbreader/zlibrary/core/src/dialogs/ZLOpenFileDialog.h b/fbreader/fbreader/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
index d0e6c7f..3009f9c 100644
--- a/fbreader/fbreader/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
+++ b/fbreader/fbreader/zlibrary/core/src/dialogs/ZLOpenFileDialog.h
@@ -27,6 +27,8 @@ class ZLFile;
 class ZLOpenFileDialog {
 
 public:
+	virtual ~ZLOpenFileDialog() {}
+
 	class Filter {
 
 	public:
diff --git a/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.cpp b/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.cpp
index 4fed308..e3a351c 100644
--- a/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.cpp
+++ b/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.cpp
@@ -23,8 +23,8 @@
 #include "ZLZDecompressor.h"
 #include "../ZLInputStream.h"
 
-const int ZLZipHeader::SignatureLocalFile = 0x04034B50;
-const int ZLZipHeader::SignatureData = 0x08074B50;
+const unsigned long ZLZipHeader::SignatureLocalFile = 0x04034B50;
+const unsigned long ZLZipHeader::SignatureData = 0x08074B50;
 
 bool ZLZipHeader::readFrom(ZLInputStream &stream) {
 	size_t startOffset = stream.offset();
diff --git a/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.h b/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.h
index 88f6608..cf53a42 100644
--- a/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.h
+++ b/fbreader/fbreader/zlibrary/core/src/filesystem/zip/ZLZipHeader.h
@@ -23,8 +23,8 @@
 class ZLInputStream;
 
 struct ZLZipHeader {
-	static const int SignatureLocalFile;
-	static const int SignatureData;
+	static const unsigned long SignatureLocalFile;
+	static const unsigned long SignatureData;
 
 	unsigned long Signature;
 	unsigned short Version;
diff --git a/fbreader/fbreader/zlibrary/core/src/language/ZLStatisticsItem.cpp b/fbreader/fbreader/zlibrary/core/src/language/ZLStatisticsItem.cpp
index ed26f00..24adbe3 100644
--- a/fbreader/fbreader/zlibrary/core/src/language/ZLStatisticsItem.cpp
+++ b/fbreader/fbreader/zlibrary/core/src/language/ZLStatisticsItem.cpp
@@ -38,9 +38,9 @@ void ZLMapBasedStatisticsItem::next() {
 
 ZLArrayBasedStatisticsItem::ZLArrayBasedStatisticsItem(size_t sequenceLength, char* sequencePtr, unsigned short* frequencyPtr, size_t index) :
 	ZLStatisticsItem(index),
-	mySequenceLength(sequenceLength),
-	mySequencePtr(sequencePtr), 
-	myFrequencyPtr(frequencyPtr) {
+	mySequencePtr(sequencePtr),
+	myFrequencyPtr(frequencyPtr),
+	mySequenceLength(sequenceLength) {
 }
 
 ZLCharSequence ZLArrayBasedStatisticsItem::sequence() const {