diff --git a/filters/karbon/ai/ailexer.cc b/filters/karbon/ai/ailexer.cc
index 935403d9..352b8f48 100644
--- a/filters/karbon/ai/ailexer.cc
+++ b/filters/karbon/ai/ailexer.cc
@@ -73,7 +73,7 @@ const char*statetoa (State state){
 
 typedef struct {
   State oldState;
-  char c;
+  signed char c;
   State newState;
   Action action;
 } Transition;
diff --git a/filters/karbon/eps/pscommentlexer.cc b/filters/karbon/eps/pscommentlexer.cc
index a321cc0d..e15dcc59 100644
--- a/filters/karbon/eps/pscommentlexer.cc
+++ b/filters/karbon/eps/pscommentlexer.cc
@@ -59,7 +59,7 @@ const char*statetoa (State state){
 
 typedef struct {
   State oldState;
-  char c;
+  signed char c;
   State newState;
   Action action;
 } Transition;
diff --git a/filters/kspread/qpro/libqpro/src/stream.cc b/filters/kspread/qpro/libqpro/src/stream.cc
index 5b96eb8a..012e18bb 100644
--- a/filters/kspread/qpro/libqpro/src/stream.cc
+++ b/filters/kspread/qpro/libqpro/src/stream.cc
@@ -114,7 +114,7 @@ QpIStream::operator void* ()
    if( cIn == 0 )
       return 0;
    else
-      return *cIn;
+      return cIn;
 }
 
 int
diff --git a/kexi/kexidb/connection.cpp b/kexi/kexidb/connection.cpp
index dd2eb76b..776285e5 100644
--- a/kexi/kexidb/connection.cpp
+++ b/kexi/kexidb/connection.cpp
@@ -2938,7 +2938,7 @@ KexiDB::QuerySchema* Connection::setupQuerySchema( const RowData &data )
 	bool ok = true;
 	const int objID = data[0].toInt(&ok);
 	if (!ok)
-		return false;
+		return 0;
 	TQString sqlText;
 	if (!loadDataBlock( objID, sqlText, "sql" )) {
 		setError(ERR_OBJECT_NOT_FOUND, 
diff --git a/kexi/kexidb/parser/parser_p.cpp b/kexi/kexidb/parser/parser_p.cpp
index df4f3323..7c223233 100644
--- a/kexi/kexidb/parser/parser_p.cpp
+++ b/kexi/kexidb/parser/parser_p.cpp
@@ -585,7 +585,7 @@ QuerySchema* buildSelectQuery(
 			if (!options->whereExpr->validate(parseInfo)) {
 				setError(parseInfo.errMsg, parseInfo.errDescr);
 				CLEANUP;
-				return false;
+				return 0;
 			}
 			querySchema->setWhereExpression(options->whereExpr);
 		}
diff --git a/kexi/main/keximainwindowimpl.cpp b/kexi/main/keximainwindowimpl.cpp
index 6730c84b..bede2259 100644
--- a/kexi/main/keximainwindowimpl.cpp
+++ b/kexi/main/keximainwindowimpl.cpp
@@ -3697,7 +3697,7 @@ KexiMainWindowImpl::openObjectFromNavigator(KexiPart::Item* item, int viewMode,
 		return 0;
 	}
 	if (!d->prj || !item)
-		return false;
+		return 0;
 #ifndef KEXI_NO_PENDING_DIALOGS
 	Private::PendingJobType pendingType;
 	KexiDialogBase *dlg = d->openedDialogFor( item, pendingType );
diff --git a/kpresenter/KPrTextObject.cpp b/kpresenter/KPrTextObject.cpp
index 2d02f6cc..d4fc82bc 100644
--- a/kpresenter/KPrTextObject.cpp
+++ b/kpresenter/KPrTextObject.cpp
@@ -2407,11 +2407,11 @@ TQDragObject * KPrTextView::newDrag( TQWidget * parent )
     oasisStore.closeContentWriter();
 
     if ( !store->open( "styles.xml" ) )
-        return false;
+        return 0;
     //manifestWriter->addManifestEntry( "styles.xml", "text/xml" );
     doc->saveOasisDocumentStyles( store, mainStyles, 0, savingContext, KPrDocument::SaveSelected /* simply means not SaveAll */ );
     if ( !store->close() ) // done with styles.xml
-        return false;
+        return 0;
 
     delete store;
 
diff --git a/kspread/kspread_canvas.cc b/kspread/kspread_canvas.cc
index 7ce1f63c..0518e274 100644
--- a/kspread/kspread_canvas.cc
+++ b/kspread/kspread_canvas.cc
@@ -246,7 +246,7 @@ Canvas::Canvas (View *_view)
   d->m_resizeObject = 0L;
   d->m_ratio = 0.0;
   d->m_isMoving = false;
-  d->m_objectDisplayAbove = false;
+  d->m_objectDisplayAbove = 0;
   d->m_isResizing = false;
 
   d->prevSpokenPointerRow = -1;
diff --git a/lib/kformula/kformuladefs.h b/lib/kformula/kformuladefs.h
index 930b8be6..d4a3739f 100644
--- a/lib/kformula/kformuladefs.h
+++ b/lib/kformula/kformuladefs.h
@@ -163,7 +163,7 @@ enum TokenElementType {
  * The struct used to store static font data.
  */
 struct InternFontTable {
-    short unicode;
+    unsigned short unicode;
     TQChar pos;
     CharClass cl;
     CharStyle style;