diff --git a/CMakeLists.txt b/CMakeLists.txt
index d158b360d..8e435da1e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -23,7 +23,7 @@ option(WITH_TESTS "Enable building of unit tests" ON)
 
 set( KEEPASSX_VERSION "0.9.0" )
 
-add_definitions(-DQT_NO_KEYWORDS -Wall)
+add_definitions(-DQT_NO_KEYWORDS -fno-exceptions -fno-rtti -Wall -Wextra -Wundef -Wold-style-cast -Wnon-virtual-dtor)
 
 if( APPLE OR MINGW )
     set( PROGNAME KeePassX )
diff --git a/src/crypto/Crypto.cpp b/src/crypto/Crypto.cpp
index 9b8a79f20..bee190f81 100644
--- a/src/crypto/Crypto.cpp
+++ b/src/crypto/Crypto.cpp
@@ -50,11 +50,12 @@ int gcry_qt_mutex_unlock(void** p_sys)
 static const struct gcry_thread_cbs gcry_threads_qt =
 {
     GCRY_THREAD_OPTION_USER,
-    NULL,
+    0,
     gcry_qt_mutex_init,
     gcry_qt_mutex_destroy,
     gcry_qt_mutex_lock,
-    gcry_qt_mutex_unlock
+    gcry_qt_mutex_unlock,
+    0, 0, 0, 0, 0, 0, 0, 0
 };
 
 Crypto::Crypto()
diff --git a/src/gui/GroupView.h b/src/gui/GroupView.h
index dba703731..7d6f12492 100644
--- a/src/gui/GroupView.h
+++ b/src/gui/GroupView.h
@@ -29,7 +29,7 @@ class GroupView : public QTreeView
     Q_OBJECT
 
 public:
-    GroupView(Database* db, QWidget* parent = 0);
+    explicit GroupView(Database* db, QWidget* parent = 0);
     void setModel(QAbstractItemModel* model);
 
 Q_SIGNALS:
diff --git a/src/keys/Key.h b/src/keys/Key.h
index b80a6b7ee..d6d878918 100644
--- a/src/keys/Key.h
+++ b/src/keys/Key.h
@@ -23,6 +23,7 @@
 class Key
 {
 public:
+    virtual ~Key() {}
     virtual QByteArray rawKey() const = 0;
     virtual Key* clone() const = 0;
 };
diff --git a/src/streams/HashedBlockStream.cpp b/src/streams/HashedBlockStream.cpp
index c758fc4e9..ba4a563ce 100644
--- a/src/streams/HashedBlockStream.cpp
+++ b/src/streams/HashedBlockStream.cpp
@@ -135,7 +135,7 @@ bool HashedBlockStream::readHashedBlock()
     }
 
     if (m_blockSize == 0) {
-        if (hash.count(static_cast<char>(0)) != 32) {
+        if (hash.count('\0') != 32) {
             // TODO error
             Q_ASSERT(false);
             return false;