diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1c8c0cd68..b26ff8fae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,7 +52,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLANGXX)
     include(cMake/ConfigureChecks.cmake)
     configure_file(config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config.h)
     add_definitions(-DHAVE_CONFIG_H)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated -Wno-write-strings")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-deprecated -Wno-write-strings")
     INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
     # get linker errors as soon as possible and not at runtime e.g. for modules
     if(UNIX)
diff --git a/src/Base/Unit.cpp b/src/Base/Unit.cpp
index b037ee283..d76dc42d3 100644
--- a/src/Base/Unit.cpp
+++ b/src/Base/Unit.cpp
@@ -338,7 +338,7 @@ QString Unit::getString(void) const
                 Sig.ThermodynamicTemperature<0?1:2 +
                 Sig.AmountOfSubstance<0?1:2 +
                 Sig.LuminoseIntensity<0?1:2 +
-                Sig.Angle<0?1:2 ;
+                Sig.Angle<0?1:2 +
                 Sig.Density<0?1:2 ;
             if (nnom > 1) ret << '(';
             bool mult=false;
diff --git a/src/Gui/CommandDoc.cpp b/src/Gui/CommandDoc.cpp
index 68fd0bef8..f1dc3b46f 100644
--- a/src/Gui/CommandDoc.cpp
+++ b/src/Gui/CommandDoc.cpp
@@ -494,7 +494,6 @@ StdCmdRevert::StdCmdRevert()
 
 void StdCmdRevert::activated(int iMsg)
 {
-    App::Document* doc = App::GetApplication().getActiveDocument();
     QMessageBox msgBox;
     msgBox.setText(qApp->translate("Std_Revert","This will discard all the changes since last file save."));
     msgBox.setInformativeText(qApp->translate("Std_Revert","Are you sure?"));
@@ -1009,7 +1008,6 @@ void StdCmdDelete::activated(int iMsg)
             if (vpedit) {
                 // check if the edited view provider is selected
                 for (std::vector<Gui::SelectionObject>::iterator ft = sel.begin(); ft != sel.end(); ++ft) {
-                    App::DocumentObject* obj = ft->getObject();
                     Gui::ViewProvider* vp = pGuiDoc->getViewProvider(ft->getObject());
                     if (vp == vpedit) {
                         if (!ft->getSubNames().empty()) {
@@ -1031,7 +1029,6 @@ void StdCmdDelete::activated(int iMsg)
                 // check if we can delete the object
                 for (std::vector<Gui::SelectionObject>::iterator ft = sel.begin(); ft != sel.end(); ++ft) {
                     App::DocumentObject* obj = ft->getObject();
-                    Gui::ViewProvider* vp = pGuiDoc->getViewProvider(ft->getObject());
                     std::vector<App::DocumentObject*> links = obj->getInList();
                     if (!links.empty()) {
                         // check if the referenced objects are groups or are selected too
diff --git a/src/Gui/Document.cpp b/src/Gui/Document.cpp
index a6bf27956..74096bf7e 100644
--- a/src/Gui/Document.cpp
+++ b/src/Gui/Document.cpp
@@ -496,7 +496,7 @@ void Document::slotChangedObject(const App::DocumentObject& Obj, const App::Prop
             SoGroup* childGroup =  viewProvider->getChildRoot();
 
             // size not the same -> build up the list new
-            if(childGroup->getNumChildren() != children.size()){
+            if(childGroup->getNumChildren() != static_cast<int>(children.size())){
 
                 childGroup->removeAllChildren();
             
diff --git a/src/Gui/GestureNavigationStyle.cpp b/src/Gui/GestureNavigationStyle.cpp
index e29bf1ffe..4f148e738 100644
--- a/src/Gui/GestureNavigationStyle.cpp
+++ b/src/Gui/GestureNavigationStyle.cpp
@@ -294,6 +294,8 @@ SbBool GestureNavigationStyle::processSoEvent(const SoEvent * const ev)
                 }
             }
             break;
+        default:
+            break;
         }
     }
     if (processed)
@@ -343,6 +345,8 @@ SbBool GestureNavigationStyle::processSoEvent(const SoEvent * const ev)
                 }
                 processed = TRUE;
                 break;
+            default:
+                break;
             }//switch key
         }
         if (processed)
@@ -474,8 +478,8 @@ SbBool GestureNavigationStyle::processSoEvent(const SoEvent * const ev)
         if (evIsButton) {
             const SoMouseButtonEvent * const event = (const SoMouseButtonEvent *) ev;
             const int button = event->getButton();
-            const SbBool press //the button was pressed (if false -> released)
-                    = event->getState() == SoButtonEvent::DOWN ? TRUE : FALSE;
+            //const SbBool press //the button was pressed (if false -> released)
+            //        = event->getState() == SoButtonEvent::DOWN ? TRUE : FALSE;
             switch(button){
             case SoMouseButtonEvent::BUTTON1:
             case SoMouseButtonEvent::BUTTON2:
@@ -495,7 +499,7 @@ SbBool GestureNavigationStyle::processSoEvent(const SoEvent * const ev)
         //the essence part 1!
         //mouse movement into camera motion. Suppress if in gesture. Ignore until threshold is surpassed.
         if (evIsLoc2 && ! this->inGesture && this->mouseMoveThresholdBroken) {
-            const SoLocation2Event * const event = (const SoLocation2Event *) ev;
+            //const SoLocation2Event * const event = (const SoLocation2Event *) ev;
             if (curmode == NavigationStyle::ZOOMING) {//doesn't happen
                 this->zoomByCursor(posn, prevnormalized);
                 processed = TRUE;
diff --git a/src/Gui/Quarter/FocusHandler.cpp b/src/Gui/Quarter/FocusHandler.cpp
index febf9634e..053ee3a75 100644
--- a/src/Gui/Quarter/FocusHandler.cpp
+++ b/src/Gui/Quarter/FocusHandler.cpp
@@ -66,6 +66,8 @@ FocusHandler::eventFilter(QObject * obj, QEvent * event)
   case QEvent::FocusOut:
     this->focusEvent("sim.coin3d.coin.InputFocus.OUT");
     break;
+  default:
+    break;
   }
   return QObject::eventFilter(obj, event);
 }
diff --git a/src/Gui/Quarter/ImageReader.cpp b/src/Gui/Quarter/ImageReader.cpp
index 2f2ecae27..aec789e46 100644
--- a/src/Gui/Quarter/ImageReader.cpp
+++ b/src/Gui/Quarter/ImageReader.cpp
@@ -54,9 +54,9 @@ ImageReader::readImage(const SbString & filename, SbImage & sbimage) const
 {
   QImage image;
   if (image.load(filename.getString())) {
-    int c;
-    int w = image.width();
-    int h = image.height();
+    //int c;
+    //int w = image.width();
+    //int h = image.height();
 
     // Keep in 8-bits mode if that was what we read
     if (image.depth() != 8 || !image.isGrayscale()) {
diff --git a/src/Gui/Quarter/QuarterWidgetP.cpp b/src/Gui/Quarter/QuarterWidgetP.cpp
index cba357ccc..36685a909 100644
--- a/src/Gui/Quarter/QuarterWidgetP.cpp
+++ b/src/Gui/Quarter/QuarterWidgetP.cpp
@@ -76,13 +76,13 @@ QuarterWidgetP::QuarterWidgetP(QuarterWidget * masterptr, const QGLWidget * shar
   initialsoeventmanager(false),
   headlight(NULL),
   cachecontext(NULL),
-  contextmenu(NULL),
   contextmenuenabled(true),
   autoredrawenabled(true),
   interactionmodeenabled(false),
   clearzbuffer(true),
   clearwindow(true),
-  addactions(true)
+  addactions(true),
+  contextmenu(NULL)
 {
   this->cachecontext = findCacheContext(masterptr, sharewidget);
 
diff --git a/src/Gui/TaskView/TaskView.cpp b/src/Gui/TaskView/TaskView.cpp
index 59af63777..760e41351 100644
--- a/src/Gui/TaskView/TaskView.cpp
+++ b/src/Gui/TaskView/TaskView.cpp
@@ -164,7 +164,7 @@ void TaskGroup::actionEvent (QActionEvent* e)
     switch (e->type()) {
     case QEvent::ActionAdded:
         {
-            QSint::ActionLabel *label = this->createItem(action);
+            this->createItem(action);
             break;
         }
     case QEvent::ActionChanged:
diff --git a/src/Gui/View3DInventorViewer.cpp b/src/Gui/View3DInventorViewer.cpp
index 7309cdfba..62db9d913 100644
--- a/src/Gui/View3DInventorViewer.cpp
+++ b/src/Gui/View3DInventorViewer.cpp
@@ -1297,9 +1297,6 @@ void View3DInventorViewer::setRenderType(const RenderType type)
         break;
     case Image:
         {
-            const SbViewportRegion vp = this->getSoRenderManager()->getViewportRegion();
-            SbVec2s size = vp.getViewportSizePixels();
-
             QGLWidget* gl = static_cast<QGLWidget*>(this->viewport());
             gl->makeCurrent();
             int w = gl->width();
diff --git a/src/Gui/propertyeditor/PropertyItem.cpp b/src/Gui/propertyeditor/PropertyItem.cpp
index 47932bb37..36adb58a7 100644
--- a/src/Gui/propertyeditor/PropertyItem.cpp
+++ b/src/Gui/propertyeditor/PropertyItem.cpp
@@ -1709,7 +1709,7 @@ QVariant PropertyEnumItem::value(const App::Property* prop) const
     const std::vector<std::string>& value = prop_enum->getEnumVector();
     long currentItem = prop_enum->getValue();
 
-    if (currentItem < 0 || currentItem >= value.size())
+    if (currentItem < 0 || currentItem >= static_cast<long>(value.size()))
         return QVariant(QString());
     return QVariant(QString::fromUtf8(value[currentItem].c_str()));
 }
diff --git a/src/Mod/Mesh/App/Core/Projection.cpp b/src/Mod/Mesh/App/Core/Projection.cpp
index ef7c7b681..aaf34ba80 100644
--- a/src/Mod/Mesh/App/Core/Projection.cpp
+++ b/src/Mod/Mesh/App/Core/Projection.cpp
@@ -396,7 +396,7 @@ bool MeshProjection::projectLineOnMesh(const MeshFacetGrid& grid,
 
     // cut all facets with plane
     std::list< std::pair<Base::Vector3f, Base::Vector3f> > cutLine;
-    unsigned long start = 0, end = 0;
+    //unsigned long start = 0, end = 0;
     for (std::vector<unsigned long>::iterator it = facets.begin(); it != facets.end(); ++it) {
         Base::Vector3f e1, e2;
         MeshGeomFacet tria = kernel.GetFacet(*it);
@@ -418,7 +418,7 @@ bool MeshProjection::projectLineOnMesh(const MeshFacetGrid& grid,
                         else
                             cutLine.push_back(std::pair<Base::Vector3f, Base::Vector3f>(v1, e1));
 
-                        start = it - facets.begin();
+                        //start = it - facets.begin();
                     }
 
                     if (*it == f2) { // end facet
@@ -427,7 +427,7 @@ bool MeshProjection::projectLineOnMesh(const MeshFacetGrid& grid,
                         else
                             cutLine.push_back(std::pair<Base::Vector3f, Base::Vector3f>(v2, e1));
 
-                        end = it - facets.begin();
+                        //end = it - facets.begin();
                     }
                 }
             }
diff --git a/src/Mod/Mesh/Gui/ViewProvider.cpp b/src/Mod/Mesh/Gui/ViewProvider.cpp
index 481a1c9bd..3af9e8c5e 100644
--- a/src/Mod/Mesh/Gui/ViewProvider.cpp
+++ b/src/Mod/Mesh/Gui/ViewProvider.cpp
@@ -568,10 +568,10 @@ bool ViewProviderMesh::exportToVrml(const char* filename, const MeshCore::Materi
     SoMaterialBinding* binding = new SoMaterialBinding;
     SoMaterial* material = new SoMaterial;
 
-    if (mat.diffuseColor.size() == coords->point.getNum()) {
+    if (static_cast<int>(mat.diffuseColor.size()) == coords->point.getNum()) {
         binding->value = SoMaterialBinding::PER_VERTEX_INDEXED;
     }
-    else if (mat.diffuseColor.size() == faces->coordIndex.getNum()/4) {
+    else if (static_cast<int>(mat.diffuseColor.size()) == faces->coordIndex.getNum()/4) {
         binding->value = SoMaterialBinding::PER_FACE_INDEXED;
     }
 
diff --git a/src/Mod/Part/App/PrimitiveFeature.cpp b/src/Mod/Part/App/PrimitiveFeature.cpp
index 676e68caf..dafefc9fe 100644
--- a/src/Mod/Part/App/PrimitiveFeature.cpp
+++ b/src/Mod/Part/App/PrimitiveFeature.cpp
@@ -826,7 +826,7 @@ App::DocumentObjectExecReturn *Helix::execute(void)
         Standard_Real myRadius = Radius.getValue();
         Standard_Real myAngle  = Angle.getValue();
         Standard_Boolean myLocalCS = LocalCoord.getValue() ? Standard_True : Standard_False;
-        Standard_Boolean myStyle = Style.getValue() ? Standard_True : Standard_False;
+        //Standard_Boolean myStyle = Style.getValue() ? Standard_True : Standard_False;
         TopoShape helix;
         // work around for OCC bug #23314 (FC #0954)
         // the exact conditions for failure are unknown.  building the helix 1 turn at a time
diff --git a/src/Mod/Part/Gui/SoBrepFaceSet.cpp b/src/Mod/Part/Gui/SoBrepFaceSet.cpp
index 0cbfeb5f1..935ef7475 100644
--- a/src/Mod/Part/Gui/SoBrepFaceSet.cpp
+++ b/src/Mod/Part/Gui/SoBrepFaceSet.cpp
@@ -866,6 +866,7 @@ void SoBrepFaceSet::renderShape(const SoGLCoordinateElement * const vertexlist,
             break;
         }
         v4 = viptr < viendptr ? *viptr++ : -1;
+        (void)v4;
 
         /* vertex 1 *********************************************************/
         if (mbind == PER_PART) {
diff --git a/src/Mod/Part/Gui/ViewProviderBoolean.cpp b/src/Mod/Part/Gui/ViewProviderBoolean.cpp
index 748dece6f..43734ad34 100644
--- a/src/Mod/Part/Gui/ViewProviderBoolean.cpp
+++ b/src/Mod/Part/Gui/ViewProviderBoolean.cpp
@@ -106,7 +106,7 @@ void ViewProviderBoolean::updateData(const App::Property* prop)
             colBool.resize(boolMap.Extent(), this->ShapeColor.getValue());
 
             bool setColor=false;
-            if (colBase.size() == baseMap.Extent()) {
+            if (static_cast<int>(colBase.size()) == baseMap.Extent()) {
                 applyColor(hist[0], colBase, colBool);
                 setColor = true;
             }
@@ -115,7 +115,7 @@ void ViewProviderBoolean::updateData(const App::Property* prop)
                 applyColor(hist[0], colBase, colBool);
                 setColor = true;
             }
-            if (colTool.size() == toolMap.Extent()) {
+            if (static_cast<int>(colTool.size()) == toolMap.Extent()) {
                 applyColor(hist[1], colTool, colBool);
                 setColor = true;
             }
@@ -199,7 +199,7 @@ void ViewProviderMultiFuse::updateData(const App::Property* prop)
 
             Gui::ViewProvider* vpBase = Gui::Application::Instance->getViewProvider(objBase);
             std::vector<App::Color> colBase = static_cast<PartGui::ViewProviderPart*>(vpBase)->DiffuseColor.getValues();
-            if (colBase.size() == baseMap.Extent()) {
+            if (static_cast<int>(colBase.size()) == baseMap.Extent()) {
                 applyColor(hist[index], colBase, colBool);
                 setColor = true;
             }
@@ -316,7 +316,7 @@ void ViewProviderMultiCommon::updateData(const App::Property* prop)
 
             Gui::ViewProvider* vpBase = Gui::Application::Instance->getViewProvider(objBase);
             std::vector<App::Color> colBase = static_cast<PartGui::ViewProviderPart*>(vpBase)->DiffuseColor.getValues();
-            if (colBase.size() == baseMap.Extent()) {
+            if (static_cast<int>(colBase.size()) == baseMap.Extent()) {
                 applyColor(hist[index], colBase, colBool);
                 setColor = true;
             }
diff --git a/src/Mod/Part/Gui/ViewProviderCompound.cpp b/src/Mod/Part/Gui/ViewProviderCompound.cpp
index 3fccded18..a9f42b5ce 100644
--- a/src/Mod/Part/Gui/ViewProviderCompound.cpp
+++ b/src/Mod/Part/Gui/ViewProviderCompound.cpp
@@ -92,7 +92,7 @@ void ViewProviderCompound::updateData(const App::Property* prop)
 
             Gui::ViewProvider* vpBase = Gui::Application::Instance->getViewProvider(objBase);
             std::vector<App::Color> baseCol = static_cast<PartGui::ViewProviderPart*>(vpBase)->DiffuseColor.getValues();
-            if (baseCol.size() == baseMap.Extent()) {
+            if (static_cast<int>(baseCol.size()) == baseMap.Extent()) {
                 applyColor(hist[index], baseCol, compCol);
                 setColor = true;
             }
diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index 3cc46fcd1..1ee28cbc6 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -762,7 +762,6 @@ void ViewProviderPartExt::updateVisual(const TopoDS_Shape& inputShape)
         bounds.Get(xMin, yMin, zMin, xMax, yMax, zMax);
         Standard_Real deflection = ((xMax-xMin)+(yMax-yMin)+(zMax-zMin))/300.0 *
             Deviation.getValue();
-        Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;
 
         // create or use the mesh on the data structure
 #if OCC_VERSION_HEX >= 0x060600
diff --git a/src/Mod/Part/Gui/ViewProviderMirror.cpp b/src/Mod/Part/Gui/ViewProviderMirror.cpp
index ba1eb2d02..b021928ec 100644
--- a/src/Mod/Part/Gui/ViewProviderMirror.cpp
+++ b/src/Mod/Part/Gui/ViewProviderMirror.cpp
@@ -253,7 +253,7 @@ void ViewProviderFillet::updateData(const App::Property* prop)
             colFill.resize(fillMap.Extent(), static_cast<PartGui::ViewProviderPart*>(vpBase)->ShapeColor.getValue());
 
             bool setColor=false;
-            if (colBase.size() == baseMap.Extent()) {
+            if (static_cast<int>(colBase.size()) == baseMap.Extent()) {
                 applyColor(hist[0], colBase, colFill);
                 setColor = true;
             }
@@ -356,7 +356,7 @@ void ViewProviderChamfer::updateData(const App::Property* prop)
             colCham.resize(chamMap.Extent(), static_cast<PartGui::ViewProviderPart*>(vpBase)->ShapeColor.getValue());
 
             bool setColor=false;
-            if (colBase.size() == baseMap.Extent()) {
+            if (static_cast<int>(colBase.size()) == baseMap.Extent()) {
                 applyColor(hist[0], colBase, colCham);
                 setColor = true;
             }
diff --git a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
index 8e7077da4..f3e7b5623 100644
--- a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
+++ b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
@@ -250,7 +250,6 @@ void ViewProviderTransformed::recomputeFeature(void)
                 bounds.Get(xMin, yMin, zMin, xMax, yMax, zMax);
             }
             Standard_Real deflection = ((xMax-xMin)+(yMax-yMin)+(zMax-zMin))/300.0 * Deviation.getValue();
-            Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;
 
             // create or use the mesh on the data structure
 #if OCC_VERSION_HEX >= 0x060600