--- a/accessible/src/atk/nsMaiInterfaceTable.cpp
+++ b/accessible/src/atk/nsMaiInterfaceTable.cpp
@@ -334,17 +334,17 @@ getSelectedColumnsCB(AtkTable *aTable, g
     if (NS_FAILED(rv) || (size == 0) || !columns) {
         *aSelected = nsnull;
         return 0;
     }
 
     gint *atkColumns = g_new(gint, size);
     if (!atkColumns) {
         NS_WARNING("OUT OF MEMORY");
-        return nsnull;
+        return 0;
     }
 
     //copy
     for (PRUint32 index = 0; index < size; ++index)
         atkColumns[index] = static_cast<gint>(columns[index]);
     nsMemory::Free(columns);
 
     *aSelected = atkColumns;
@@ -369,17 +369,17 @@ getSelectedRowsCB(AtkTable *aTable, gint
     if (NS_FAILED(rv) || (size == 0) || !rows) {
         *aSelected = nsnull;
         return 0;
     }
 
     gint *atkRows = g_new(gint, size);
     if (!atkRows) {
         NS_WARNING("OUT OF MEMORY");
-        return nsnull;
+        return 0;
     }
 
     //copy
     for (PRUint32 index = 0; index < size; ++index)
         atkRows[index] = static_cast<gint>(rows[index]);
     nsMemory::Free(rows);
 
     *aSelected = atkRows;

--- a/accessible/src/atk/nsMaiInterfaceText.cpp
+++ b/accessible/src/atk/nsMaiInterfaceText.cpp
@@ -344,22 +344,22 @@ getOffsetAtPointCB(AtkText *aText,
     return static_cast<gint>(offset);
 }
 
 static gint
 getTextSelectionCountCB(AtkText *aText)
 {
   AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aText));
   if (!accWrap)
-    return nsnull;
+    return 0;
 
     nsCOMPtr<nsIAccessibleText> accText;
     accWrap->QueryInterface(NS_GET_IID(nsIAccessibleText),
                             getter_AddRefs(accText));
-    NS_ENSURE_TRUE(accText, nsnull);
+    NS_ENSURE_TRUE(accText, 0);
 
     PRInt32 selectionCount;
     nsresult rv = accText->GetSelectionCount(&selectionCount);
  
     return NS_FAILED(rv) ? 0 : selectionCount;
 }
 
 static gchar*

--- a/accessible/src/generic/HyperTextAccessible.cpp
+++ b/accessible/src/generic/HyperTextAccessible.cpp
@@ -477,17 +477,17 @@ HyperTextAccessible::GetCharacterCount(P
 
 /*
  * Gets the specified character.
  */
 NS_IMETHODIMP
 HyperTextAccessible::GetCharacterAtOffset(PRInt32 aOffset, PRUnichar* aCharacter)
 {
   NS_ENSURE_ARG_POINTER(aCharacter);
-  *aCharacter = nsnull;
+  *aCharacter = L'\0';
 
   if (IsDefunct())
     return NS_ERROR_FAILURE;
 
   nsAutoString character;
   if (GetCharAt(aOffset, eGetAt, character)) {
     *aCharacter = character.First();
     return NS_OK;

--- a/configure.in
+++ b/configure.in
@@ -2766,16 +2766,31 @@ dnl Note that we assume that mac & win32
         else
             WCHAR_CFLAGS="-fshort-wchar"
         fi
     else
         CXXFLAGS=$_SAVE_CXXFLAGS
     fi
 fi
 
+dnl Check for nullptr (bug 626472)
+AC_LANG_CPLUSPLUS
+AC_MSG_CHECKING(for nullptr)
+AC_CACHE_VAL(ac_cv_nullptr,
+ [AC_TRY_COMPILE([],
+                 [int* foo = nullptr;],
+                 [ac_cv_nullptr=true],
+                 [ac_cv_nullptr=false])])
+if test "$ac_cv_nullptr" = true ; then
+  AC_DEFINE(HAVE_NULLPTR)
+  AC_MSG_RESULT(yes)
+else
+  AC_MSG_RESULT(no)
+fi
+
 AC_LANG_C
 
 dnl Check for .hidden assembler directive and visibility attribute.
 dnl Borrowed from glibc configure.in
 dnl ===============================================================
 if test "$GNU_CC"; then
   AC_CACHE_CHECK(for visibility(hidden) attribute,
                  ac_cv_visibility_hidden,

--- a/content/base/src/nsAttrAndChildArray.cpp
+++ b/content/base/src/nsAttrAndChildArray.cpp
@@ -457,17 +457,17 @@ nsAttrAndChildArray::RemoveAttrAt(PRUint
   aPos -= mapped;
   ATTRS(mImpl)[aPos].mValue.SwapValueWith(aValue);
   ATTRS(mImpl)[aPos].~InternalAttr();
 
   PRUint32 slotCount = AttrSlotCount();
   memmove(&ATTRS(mImpl)[aPos],
           &ATTRS(mImpl)[aPos + 1],
           (slotCount - aPos - 1) * sizeof(InternalAttr));
-  memset(&ATTRS(mImpl)[slotCount - 1], nsnull, sizeof(InternalAttr));
+  memset(&ATTRS(mImpl)[slotCount - 1], 0, sizeof(InternalAttr));
 
   return NS_OK;
 }
 
 const nsAttrName*
 nsAttrAndChildArray::AttrNameAt(PRUint32 aPos) const
 {
   NS_ASSERTION(aPos < AttrCount(),

--- a/content/events/src/nsEventListenerManager.cpp
+++ b/content/events/src/nsEventListenerManager.cpp
@@ -597,17 +597,17 @@ nsEventListenerManager::AddScriptEventLi
         // build a "script sample" based on what we know about this element
         scriptSample.Assign(attr);
         scriptSample.AppendLiteral(" attribute on ");
         scriptSample.Append(tagName);
         scriptSample.AppendLiteral(" element");
         csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_SCRIPT,
                                  NS_ConvertUTF8toUTF16(asciiSpec),
                                  scriptSample,
-                                 nsnull);
+                                 0);
         return NS_OK;
       }
     }
   }
 
   // This might be the first reference to this language in the global
   // We must init the language before we attempt to fetch its context.
   if (NS_FAILED(global->EnsureScriptEnvironment())) {

--- a/content/html/content/src/nsHTMLFormElement.cpp
+++ b/content/html/content/src/nsHTMLFormElement.cpp
@@ -986,17 +986,17 @@ nsHTMLFormElement::WalkFormElements(nsFo
   return NS_OK;
 }
 
 // nsIForm
 
 NS_IMETHODIMP_(PRUint32)
 nsHTMLFormElement::GetElementCount() const 
 {
-  PRUint32 count = nsnull;
+  PRUint32 count = 0;
   mControls->GetLength(&count); 
   return count;
 }
 
 NS_IMETHODIMP_(nsIFormControl*)
 nsHTMLFormElement::GetElementAt(PRInt32 aIndex) const
 {
   return mControls->mElements.SafeElementAt(aIndex, nsnull);
@@ -1847,18 +1847,18 @@ nsHTMLFormElement::OnSecurityChange(nsIW
 {
   NS_NOTREACHED("notification excluded in AddProgressListener(...)");
   return NS_OK;
 }
  
 NS_IMETHODIMP_(PRInt32)
 nsHTMLFormElement::IndexOfControl(nsIFormControl* aControl)
 {
-  PRInt32 index = nsnull;
-  return mControls->IndexOfControl(aControl, &index) == NS_OK ? index : nsnull;
+  PRInt32 index = 0;
+  return mControls->IndexOfControl(aControl, &index) == NS_OK ? index : 0;
 }
 
 NS_IMETHODIMP
 nsHTMLFormElement::SetCurrentRadioButton(const nsAString& aName,
                                          nsIDOMHTMLInputElement* aRadio)
 {
   mSelectedRadioButtons.Put(aName, aRadio);
 

--- a/content/media/ogg/nsOggReader.cpp
+++ b/content/media/ogg/nsOggReader.cpp
@@ -729,19 +729,19 @@ GetChecksum(ogg_page* page)
                (p[3] << 24);
   return c;
 }
 
 PRInt64 nsOggReader::RangeStartTime(PRInt64 aOffset)
 {
   NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");
   MediaResource* resource = mDecoder->GetResource();
-  NS_ENSURE_TRUE(resource != nsnull, nsnull);
+  NS_ENSURE_TRUE(resource != nsnull, 0);
   nsresult res = resource->Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
-  NS_ENSURE_SUCCESS(res, nsnull);
+  NS_ENSURE_SUCCESS(res, 0);
   PRInt64 startTime = 0;
   nsBuiltinDecoderReader::FindStartTime(startTime);
   return startTime;
 }
 
 struct nsAutoOggSyncState {
   nsAutoOggSyncState() {
     ogg_sync_init(&mState);

--- a/content/xbl/src/nsXBLPrototypeHandler.cpp
+++ b/content/xbl/src/nsXBLPrototypeHandler.cpp
@@ -107,17 +107,17 @@ nsXBLPrototypeHandler::nsXBLPrototypeHan
   Init();
 
   // Make sure our prototype is initialized.
   ConstructPrototype(aHandlerElement);
 }
 
 nsXBLPrototypeHandler::nsXBLPrototypeHandler(nsXBLPrototypeBinding* aBinding)
   : mHandlerText(nsnull),
-    mLineNumber(nsnull),
+    mLineNumber(0),
     mNextHandler(nsnull),
     mPrototypeBinding(aBinding)
 {
   Init();
 }
 
 nsXBLPrototypeHandler::~nsXBLPrototypeHandler()
 {

--- a/dom/indexedDB/IndexedDatabaseManager.cpp
+++ b/dom/indexedDB/IndexedDatabaseManager.cpp
@@ -380,17 +380,17 @@ IndexedDatabaseManager::FireWindowOnErro
   // Log an error to the error console.
   nsCOMPtr<nsIScriptError> scriptError =
     do_CreateInstance(NS_SCRIPTERROR_CONTRACTID, &rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (NS_FAILED(scriptError->InitWithWindowID(event.errorMsg,
                                               event.fileName,
                                               nsnull, event.lineNr,
-                                              nsnull, 0,
+                                              0, 0,
                                               "IndexedDB",
                                               aOwner->WindowID()))) {
     NS_WARNING("Failed to init script error!");
     return NS_ERROR_FAILURE;
   }
 
   nsCOMPtr<nsIConsoleService> consoleService =
     do_GetService(NS_CONSOLESERVICE_CONTRACTID, &rv);

--- a/dom/plugins/base/nsNPAPIPlugin.cpp
+++ b/dom/plugins/base/nsNPAPIPlugin.cpp
@@ -1994,17 +1994,17 @@ NPError NP_CALLBACK
   case NPNVnetscapeWindow: {
     if (!npp || !npp->ndata)
       return NPERR_INVALID_INSTANCE_ERROR;
 
     nsNPAPIPluginInstance *inst = (nsNPAPIPluginInstance *) npp->ndata;
 
     nsCOMPtr<nsIPluginInstanceOwner> owner;
     inst->GetOwner(getter_AddRefs(owner));
-    NS_ENSURE_TRUE(owner, nsnull);
+    NS_ENSURE_TRUE(owner, NPERR_NO_ERROR);
 
     if (NS_SUCCEEDED(owner->GetNetscapeWindow(result))) {
       return NPERR_NO_ERROR;
     }
     return NPERR_GENERIC_ERROR;
   }
 #endif
 

--- a/dom/plugins/base/nsPluginHost.cpp
+++ b/dom/plugins/base/nsPluginHost.cpp
@@ -584,17 +584,17 @@ nsresult nsPluginHost::GetURL(nsISupport
                               const char* target,
                               nsNPAPIPluginStreamListener* streamListener,
                               const char* altHost,
                               const char* referrer,
                               bool forceJSEnabled)
 {
   return GetURLWithHeaders(static_cast<nsNPAPIPluginInstance*>(pluginInst),
                            url, target, streamListener, altHost, referrer,
-                           forceJSEnabled, nsnull, nsnull);
+                           forceJSEnabled, 0, nsnull);
 }
 
 nsresult nsPluginHost::GetURLWithHeaders(nsNPAPIPluginInstance* pluginInst,
                                          const char* url,
                                          const char* target,
                                          nsNPAPIPluginStreamListener* streamListener,
                                          const char* altHost,
                                          const char* referrer,

--- a/dom/src/json/nsJSON.cpp
+++ b/dom/src/json/nsJSON.cpp
@@ -281,17 +281,17 @@ nsJSONWriter::SetCharset(const char* aCh
   nsresult rv = NS_OK;
   if (mStream) {
     nsCOMPtr<nsICharsetConverterManager> ccm =
       do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
     rv = ccm->GetUnicodeEncoder(aCharset, getter_AddRefs(mEncoder));
     NS_ENSURE_SUCCESS(rv, rv);
     rv = mEncoder->SetOutputErrorBehavior(nsIUnicodeEncoder::kOnError_Signal,
-                                          nsnull, nsnull);
+                                          nsnull, '\0');
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   return rv;
 }
 
 nsresult
 nsJSONWriter::Write(const PRUnichar *aBuffer, PRUint32 aLength)

--- a/dom/src/jsurl/nsJSProtocolHandler.cpp
+++ b/dom/src/jsurl/nsJSProtocolHandler.cpp
@@ -172,17 +172,17 @@ nsresult nsJSThunk::EvaluateScript(nsICh
           // gather information to log with violation report
           nsCOMPtr<nsIURI> uri;
           principal->GetURI(getter_AddRefs(uri));
           nsCAutoString asciiSpec;
           uri->GetAsciiSpec(asciiSpec);
 		  csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_SCRIPT,
 								   NS_ConvertUTF8toUTF16(asciiSpec),
 								   NS_ConvertUTF8toUTF16(mURL),
-                                   nsnull);
+                                   0);
           return NS_ERROR_DOM_RETVAL_UNDEFINED;
       }
     }
 
     // Get the global object we should be running on.
     nsIScriptGlobalObject* global = GetGlobalObject(aChannel);
     if (!global) {
         return NS_ERROR_FAILURE;

--- a/editor/libeditor/text/nsPlaintextDataTransfer.cpp
+++ b/editor/libeditor/text/nsPlaintextDataTransfer.cpp
@@ -336,17 +336,17 @@ NS_IMETHODIMP nsPlaintextEditor::Paste(P
     // Get the Data from the clipboard  
     if (NS_SUCCEEDED(clipboard->GetData(trans, aSelectionType)) && IsModifiable())
     {
       // handle transferable hooks
       nsCOMPtr<nsIDOMDocument> domdoc = GetDOMDocument();
       if (!nsEditorHookUtils::DoInsertionHook(domdoc, nsnull, trans))
         return NS_OK;
 
-      rv = InsertTextFromTransferable(trans, nsnull, nsnull, true);
+      rv = InsertTextFromTransferable(trans, nsnull, 0, true);
     }
   }
 
   return rv;
 }
 
 NS_IMETHODIMP nsPlaintextEditor::PasteTransferable(nsITransferable *aTransferable)
 {
@@ -356,17 +356,17 @@ NS_IMETHODIMP nsPlaintextEditor::PasteTr
   if (!IsModifiable())
     return NS_OK;
 
   // handle transferable hooks
   nsCOMPtr<nsIDOMDocument> domdoc = GetDOMDocument();
   if (!nsEditorHookUtils::DoInsertionHook(domdoc, nsnull, aTransferable))
     return NS_OK;
 
-  return InsertTextFromTransferable(aTransferable, nsnull, nsnull, true);
+  return InsertTextFromTransferable(aTransferable, nsnull, 0, true);
 }
 
 NS_IMETHODIMP nsPlaintextEditor::CanPaste(PRInt32 aSelectionType, bool *aCanPaste)
 {
   NS_ENSURE_ARG_POINTER(aCanPaste);
   *aCanPaste = false;
 
   // can't paste if readonly

--- a/gfx/gl/GLContext.h
+++ b/gfx/gl/GLContext.h
@@ -854,17 +854,17 @@ public:
 
     virtual bool SupportsOffscreenSplit() {
         return IsExtensionSupported(EXT_framebuffer_blit) || IsExtensionSupported(ANGLE_framebuffer_blit);
     }
 
     /**
      * Create new shared GLContext content handle, must be released by ReleaseSharedHandle.
      */
-    virtual SharedTextureHandle CreateSharedHandle(TextureImage::TextureShareType aType) { return nsnull; }
+    virtual SharedTextureHandle CreateSharedHandle(TextureImage::TextureShareType aType) { return 0; }
     /**
      * Publish GLContext content to intermediate buffer attached to shared handle.
      * Shared handle content is ready to be used after call returns, and no need extra Flush/Finish are required.
      * GLContext must be current before this call
      */
     virtual void UpdateSharedHandle(TextureImage::TextureShareType aType,
                                     SharedTextureHandle aSharedHandle) { }
     /**

--- a/gfx/layers/basic/BasicCanvasLayer.cpp
+++ b/gfx/layers/basic/BasicCanvasLayer.cpp
@@ -331,17 +331,17 @@ public:
 
 private:
   typedef mozilla::gl::SharedTextureHandle SharedTextureHandle;
   typedef mozilla::gl::TextureImage TextureImage;
   SharedTextureHandle GetSharedBackBufferHandle()
   {
     if (mBackBuffer.type() == SurfaceDescriptor::TSharedTextureDescriptor)
       return mBackBuffer.get_SharedTextureDescriptor().handle();
-    return nsnull;
+    return 0;
   }
 
   BasicShadowLayerManager* BasicManager()
   {
     return static_cast<BasicShadowLayerManager*>(mManager);
   }
 
   SurfaceDescriptor mBackBuffer;

--- a/gfx/thebes/gfxFontUtils.cpp
+++ b/gfx/thebes/gfxFontUtils.cpp
@@ -546,17 +546,17 @@ gfxFontUtils::FindPreferredSubtable(cons
         EncodingIDMicrosoft = 1,
         EncodingIDDefaultForUnicodePlatform = 0,
         EncodingIDUCS4ForUnicodePlatform = 3,
         EncodingIDUVSForUnicodePlatform = 5,
         EncodingIDUCS4ForMicrosoftPlatform = 10
     };
 
     if (aUVSTableOffset) {
-        *aUVSTableOffset = nsnull;
+        *aUVSTableOffset = 0;
     }
 
     if (!aBuf || aBufLength < SizeOfHeader) {
         // cmap table is missing, or too small to contain header fields!
         return 0;
     }
 
     // PRUint16 version = ReadShortAt(aBuf, OffsetVersion); // Unused: self-documenting.

--- a/gfx/thebes/nsCoreAnimationSupport.h
+++ b/gfx/thebes/nsCoreAnimationSupport.h
@@ -22,19 +22,19 @@ CGColorSpaceRef THEBES_API CreateSystemC
 struct _CGLPBufferObject;
 struct _CGLContextObject;
 
 enum AllowOfflineRendererEnum { ALLOW_OFFLINE_RENDERER, DISALLOW_OFFLINE_RENDERER };
 
 class THEBES_API nsCARenderer {
   NS_INLINE_DECL_REFCOUNTING(nsCARenderer)
 public:
-  nsCARenderer() : mCARenderer(nsnull), mFBOTexture(nsnull), mOpenGLContext(nsnull),
-                   mCGImage(nsnull), mCGData(nsnull), mIOSurface(nsnull), mFBO(nsnull),
-                   mIOTexture(nsnull),
+  nsCARenderer() : mCARenderer(nsnull), mFBOTexture(0), mOpenGLContext(nsnull),
+                   mCGImage(nsnull), mCGData(nsnull), mIOSurface(nsnull), mFBO(0),
+                   mIOTexture(0),
                    mUnsupportedWidth(UINT32_MAX), mUnsupportedHeight(UINT32_MAX),
                    mAllowOfflineRenderer(DISALLOW_OFFLINE_RENDERER) {}
   ~nsCARenderer();
   nsresult SetupRenderer(void* aCALayer, int aWidth, int aHeight,
                          AllowOfflineRendererEnum aAllowOfflineRenderer);
   nsresult Render(int aWidth, int aHeight, CGImageRef *aOutCAImage);
   bool isInit() { return mCARenderer != nsnull; }
   /*

--- a/gfx/thebes/nsCoreAnimationSupport.mm
+++ b/gfx/thebes/nsCoreAnimationSupport.mm
@@ -426,18 +426,18 @@ void nsCARenderer::Destroy() {
   }
   // mCGData is deallocated by cgdata_release_callback
 
   mCARenderer = nil;
   mFBOTexture = 0;
   mOpenGLContext = nsnull;
   mCGImage = nsnull;
   mIOSurface = nsnull;
-  mFBO = nsnull;
-  mIOTexture = nsnull;
+  mFBO = 0;
+  mIOTexture = 0;
 }
 
 nsresult nsCARenderer::SetupRenderer(void *aCALayer, int aWidth, int aHeight,
                                      AllowOfflineRendererEnum aAllowOfflineRenderer) {
   mAllowOfflineRenderer = aAllowOfflineRenderer;
 
   if (aWidth == 0 || aHeight == 0)
     return NS_ERROR_FAILURE;

--- a/layout/generic/nsBulletFrame.cpp
+++ b/layout/generic/nsBulletFrame.cpp
@@ -406,30 +406,30 @@ static bool OtherDecimalToText(PRInt32 o
 {
    PRUnichar diff = zeroChar - PRUnichar('0');
    DecimalToText(ordinal, result);
    PRUnichar* p = result.BeginWriting();
    if (ordinal < 0) {
      // skip the leading '-'
      ++p;
    }     
-   for(; nsnull != *p ; p++) 
+   for(; '\0' != *p ; p++) 
       *p += diff;
    return true;
 }
 static bool TamilToText(PRInt32 ordinal,  nsString& result)
 {
    PRUnichar diff = 0x0BE6 - PRUnichar('0');
    DecimalToText(ordinal, result); 
    if (ordinal < 1 || ordinal > 9999) {
      // Can't do those in this system.
      return false;
    }
    PRUnichar* p = result.BeginWriting();
-   for(; nsnull != *p ; p++) 
+   for(; '\0' != *p ; p++) 
       if(*p != PRUnichar('0'))
          *p += diff;
    return true;
 }
 
 
 static const char gLowerRomanCharsA[] = "ixcm";
 static const char gUpperRomanCharsA[] = "IXCM";

--- a/layout/printing/nsPrintData.cpp
+++ b/layout/printing/nsPrintData.cpp
@@ -29,17 +29,17 @@ static PRLogModuleInfo * kPrintingLogMod
 #define PR_PL(_p1)
 #endif
 
 //---------------------------------------------------
 //-- nsPrintData Class Impl
 //---------------------------------------------------
 nsPrintData::nsPrintData(ePrintDataType aType) :
   mType(aType), mDebugFilePtr(nsnull), mPrintObject(nsnull), mSelectedPO(nsnull),
-  mPrintDocList(nsnull), mIsIFrameSelected(false),
+  mPrintDocList(0), mIsIFrameSelected(false),
   mIsParentAFrameSet(false), mOnStartSent(false),
   mIsAborted(false), mPreparingForPrint(false), mDocWasToBeDestroyed(false),
   mShrinkToFit(false), mPrintFrameType(nsIPrintSettings::kFramesAsIs), 
   mNumPrintablePages(0), mNumPagesPrinted(0),
   mShrinkRatio(1.0), mOrigDCScale(1.0), mPPEventListeners(NULL), 
   mBrandName(nsnull)
 {
   MOZ_COUNT_CTOR(nsPrintData);

--- a/layout/printing/nsPrintEngine.cpp
+++ b/layout/printing/nsPrintEngine.cpp
@@ -3175,17 +3175,17 @@ nsPrintEngine::TurnScriptingOn(bool aDoT
 //-- Section: Finishing up or Cleaning up
 //-----------------------------------------------------------------
 
 //-----------------------------------------------------------------
 void
 nsPrintEngine::CloseProgressDialog(nsIWebProgressListener* aWebProgressListener)
 {
   if (aWebProgressListener) {
-    aWebProgressListener->OnStateChange(nsnull, nsnull, nsIWebProgressListener::STATE_STOP|nsIWebProgressListener::STATE_IS_DOCUMENT, nsnull);
+    aWebProgressListener->OnStateChange(nsnull, nsnull, nsIWebProgressListener::STATE_STOP|nsIWebProgressListener::STATE_IS_DOCUMENT, NS_OK);
   }
 }
 
 //-----------------------------------------------------------------
 nsresult
 nsPrintEngine::FinishPrintPreview()
 {
   nsresult rv = NS_OK;

--- a/layout/style/nsCSSRuleProcessor.cpp
+++ b/layout/style/nsCSSRuleProcessor.cpp
@@ -501,17 +501,17 @@ protected:
   PRUint32    mElementTagCalls;
   PRUint32    mElementClassCalls;
   PRUint32    mElementIdCalls;
 #endif // RULE_HASH_STATS
 };
 
 RuleHash::RuleHash(bool aQuirksMode)
   : mRuleCount(0),
-    mUniversalRules(nsnull),
+    mUniversalRules(0),
     mEnumList(nsnull), mEnumListSize(0),
     mQuirksMode(aQuirksMode)
 #ifdef RULE_HASH_STATS
     ,
     mUniversalSelectors(0),
     mNameSpaceSelectors(0),
     mTagSelectors(0),
     mClassSelectors(0),

--- a/layout/svg/base/src/nsSVGGradientFrame.cpp
+++ b/layout/svg/base/src/nsSVGGradientFrame.cpp
@@ -384,17 +384,17 @@ nsSVGGradientFrame::GetStopFrame(PRInt32
     return stopCount;
   }
 
   // Our gradient element doesn't have stops - try to "inherit" them
 
   AutoGradientReferencer gradientRef(this);
   nsSVGGradientFrame* next = GetReferencedGradientIfNotInUse();
   if (!next)
-    return nsnull;
+    return 0;
 
   return next->GetStopFrame(aIndex, aStopFrame);
 }
 
 // -------------------------------------------------------------------------
 // Linear Gradients
 // -------------------------------------------------------------------------
 

--- a/layout/xul/base/src/nsDocElementBoxFrame.cpp
+++ b/layout/xul/base/src/nsDocElementBoxFrame.cpp
@@ -106,17 +106,17 @@ nsDocElementBoxFrame::CreateAnonymousCon
   nodeInfo = nodeInfoManager->GetNodeInfo(nsGkAtoms::tooltip, nsnull,
                                           kNameSpaceID_XUL,
                                           nsIDOMNode::ELEMENT_NODE);
   NS_ENSURE_TRUE(nodeInfo, NS_ERROR_OUT_OF_MEMORY);
 
   rv = NS_NewXULElement(getter_AddRefs(mTooltipContent), nodeInfo.forget());
   NS_ENSURE_SUCCESS(rv, rv);
 
-  mTooltipContent->SetAttr(nsnull, nsGkAtoms::_default,
+  mTooltipContent->SetAttr(kNameSpaceID_None, nsGkAtoms::_default,
                            NS_LITERAL_STRING("true"), false);
 
   if (!aElements.AppendElement(mTooltipContent))
     return NS_ERROR_OUT_OF_MEMORY;
 
   return NS_OK;
 }
 

--- a/layout/xul/base/src/nsXULTooltipListener.cpp
+++ b/layout/xul/base/src/nsXULTooltipListener.cpp
@@ -491,19 +491,19 @@ nsXULTooltipListener::LaunchTooltip()
     nsCOMPtr<nsITreeBoxObject> obx;
     GetSourceTreeBoxObject(getter_AddRefs(obx));
 
     SetTitletipLabel(obx, currentTooltip, mLastTreeRow, mLastTreeCol);
     if (!(currentTooltip = do_QueryReferent(mCurrentTooltip))) {
       // Because of mutation events, currentTooltip can be null.
       return;
     }
-    currentTooltip->SetAttr(nsnull, nsGkAtoms::titletip, NS_LITERAL_STRING("true"), true);
+    currentTooltip->SetAttr(kNameSpaceID_None, nsGkAtoms::titletip, NS_LITERAL_STRING("true"), true);
   } else {
-    currentTooltip->UnsetAttr(nsnull, nsGkAtoms::titletip, true);
+    currentTooltip->UnsetAttr(kNameSpaceID_None, nsGkAtoms::titletip, true);
   }
   if (!(currentTooltip = do_QueryReferent(mCurrentTooltip))) {
     // Because of mutation events, currentTooltip can be null.
     return;
   }
 
   nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
   if (pm) {

--- a/netwerk/base/src/nsTransportUtils.cpp
+++ b/netwerk/base/src/nsTransportUtils.cpp
@@ -72,17 +72,17 @@ public:
         {
             MutexAutoLock lock(mProxy->mLock);
             if (mProxy->mLastEvent == this)
                 mProxy->mLastEvent = nsnull;
         }
 
         mProxy->mSink->OnTransportStatus(mTransport, mStatus, mProgress,
                                          mProgressMax);
-        return nsnull;
+        return NS_OK;
     }
 
     nsRefPtr<nsTransportEventSinkProxy> mProxy;
 
     // parameters to OnTransportStatus
     nsCOMPtr<nsITransport> mTransport;
     nsresult               mStatus;
     PRUint64               mProgress;

--- a/netwerk/wifi/nsWifiAccessPoint.cpp
+++ b/netwerk/wifi/nsWifiAccessPoint.cpp
@@ -13,18 +13,18 @@ extern PRLogModuleInfo *gWifiMonitorLog;
 #define LOG(args)     PR_LOG(gWifiMonitorLog, PR_LOG_DEBUG, args)
 
 
 NS_IMPL_THREADSAFE_ISUPPORTS1(nsWifiAccessPoint, nsIWifiAccessPoint)
 
 nsWifiAccessPoint::nsWifiAccessPoint()
 {
   // make sure these are null terminated (because we are paranoid)
-  mMac[0] = nsnull;
-  mSsid[0] = nsnull;
+  mMac[0] = '\0';
+  mSsid[0] = '\0';
   mSsidLen = 0;
 }
 
 nsWifiAccessPoint::~nsWifiAccessPoint()
 {
 }
 
 NS_IMETHODIMP nsWifiAccessPoint::GetMac(nsACString& aMac)

--- a/parser/html/nsHtml5HtmlAttributes.cpp
+++ b/parser/html/nsHtml5HtmlAttributes.cpp
@@ -111,17 +111,17 @@ nsHtml5HtmlAttributes::getAttributeName(
 }
 
 PRInt32 
 nsHtml5HtmlAttributes::getURI(PRInt32 index)
 {
   if (index < length && index >= 0) {
     return names[index]->getUri(mode);
   } else {
-    return nsnull;
+    return 0;
   }
 }
 
 nsIAtom* 
 nsHtml5HtmlAttributes::getPrefix(PRInt32 index)
 {
   if (index < length && index >= 0) {
     return names[index]->getPrefix(mode);

--- a/parser/html/nsHtml5Tokenizer.cpp
+++ b/parser/html/nsHtml5Tokenizer.cpp
@@ -3901,18 +3901,18 @@ nsHtml5Tokenizer::emitOrAppendOne(const 
   } else {
     tokenHandler->characters(val, 0, 1);
   }
 }
 
 void 
 nsHtml5Tokenizer::end()
 {
-  strBuf = nsnull;
-  longStrBuf = nsnull;
+  strBuf = 0;
+  longStrBuf = 0;
   doctypeName = nsnull;
   if (systemIdentifier) {
     nsHtml5Portability::releaseString(systemIdentifier);
     systemIdentifier = nsnull;
   }
   if (publicIdentifier) {
     nsHtml5Portability::releaseString(publicIdentifier);
     publicIdentifier = nsnull;

--- a/parser/html/nsHtml5TreeBuilder.cpp
+++ b/parser/html/nsHtml5TreeBuilder.cpp
@@ -543,28 +543,28 @@ nsHtml5TreeBuilder::endTokenization()
   formPointer = nsnull;
   headPointer = nsnull;
   deepTreeSurrogateParent = nsnull;
   if (stack) {
     while (currentPtr > -1) {
       stack[currentPtr]->release();
       currentPtr--;
     }
-    stack = nsnull;
+    stack = 0;
   }
   if (listOfActiveFormattingElements) {
     while (listPtr > -1) {
       if (listOfActiveFormattingElements[listPtr]) {
         listOfActiveFormattingElements[listPtr]->release();
       }
       listPtr--;
     }
-    listOfActiveFormattingElements = nsnull;
+    listOfActiveFormattingElements = 0;
   }
-  charBuffer = nsnull;
+  charBuffer = 0;
   end();
 }
 
 void 
 nsHtml5TreeBuilder::startTag(nsHtml5ElementName* elementName, nsHtml5HtmlAttributes* attributes, bool selfClosing)
 {
   flushCharacters();
   PRInt32 eltPos;

--- a/parser/htmlparser/src/CNavDTD.cpp
+++ b/parser/htmlparser/src/CNavDTD.cpp
@@ -1093,17 +1093,17 @@ CNavDTD::HandleKeyGen(nsIParserNode* aNo
 
   theFormType.AssignLiteral("select");
 
   result = theFormProcessor->ProvideContent(theFormType, theContent,
                                             theAttribute);
   if (NS_FAILED(result)) {
     return result;
   }
-  PRInt32   theIndex = nsnull;
+  PRInt32   theIndex = 0;
 
   // Populate the tokenizer with the fabricated elements in the reverse
   // order such that <SELECT> is on the top fo the tokenizer followed by
   // <OPTION>s and </SELECT>.
   theToken = mTokenAllocator->CreateTokenOfType(eToken_end,
                                                 eHTMLTag_select);
   NS_ENSURE_TRUE(theToken, NS_ERROR_OUT_OF_MEMORY);
   mTokenizer->PushTokenFront(theToken);

--- a/storage/src/mozStorageAsyncStatement.cpp
+++ b/storage/src/mozStorageAsyncStatement.cpp
@@ -95,17 +95,17 @@ public:
   {
     *_language = nsIProgrammingLanguage::CPLUSPLUS;
     return NS_OK;
   }
 
   NS_IMETHODIMP
   GetFlags(PRUint32 *_flags)
   {
-    *_flags = nsnull;
+    *_flags = 0;
     return NS_OK;
   }
 
   NS_IMETHODIMP
   GetClassIDNoAlloc(nsCID *_cid)
   {
     return NS_ERROR_NOT_AVAILABLE;
   }

--- a/storage/src/mozStorageStatement.cpp
+++ b/storage/src/mozStorageStatement.cpp
@@ -98,17 +98,17 @@ public:
   {
     *_language = nsIProgrammingLanguage::CPLUSPLUS;
     return NS_OK;
   }
 
   NS_IMETHODIMP
   GetFlags(PRUint32 *_flags)
   {
-    *_flags = nsnull;
+    *_flags = 0;
     return NS_OK;
   }
 
   NS_IMETHODIMP
   GetClassIDNoAlloc(nsCID *_cid)
   {
     return NS_ERROR_NOT_AVAILABLE;
   }

--- a/storage/test/test_AsXXX_helpers.cpp
+++ b/storage/test/test_AsXXX_helpers.cpp
@@ -31,23 +31,23 @@ Spinner::HandleResult(mozIStorageResultS
   nsCOMPtr<mozIStorageRow> row;
   do_check_true(NS_SUCCEEDED(aResultSet->GetNextRow(getter_AddRefs(row))) && row);
 
   do_check_eq(row->AsInt32(0), 0);
   do_check_eq(row->AsInt64(0), 0);
   do_check_eq(row->AsDouble(0), 0.0);
 
   PRUint32 len = 100;
-  do_check_eq(row->AsSharedUTF8String(0, &len), nsnull);
+  do_check_eq(row->AsSharedUTF8String(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(row->AsSharedWString(0, &len), nsnull);
+  do_check_eq(row->AsSharedWString(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(row->AsSharedBlob(0, &len), nsnull);
+  do_check_eq(row->AsSharedBlob(0, &len), NULL);
   do_check_eq(len, 0);
 
   do_check_eq(row->IsNull(0), true);
   return NS_OK;
 }
 
 void
 test_NULLFallback()
@@ -64,37 +64,37 @@ test_NULLFallback()
 
   bool hasMore;
   do_check_true(NS_SUCCEEDED(stmt->ExecuteStep(&hasMore)) && hasMore);
 
   do_check_eq(stmt->AsInt32(0), 0);
   do_check_eq(stmt->AsInt64(0), 0);
   do_check_eq(stmt->AsDouble(0), 0.0);
   PRUint32 len = 100;
-  do_check_eq(stmt->AsSharedUTF8String(0, &len), nsnull);
+  do_check_eq(stmt->AsSharedUTF8String(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(stmt->AsSharedWString(0, &len), nsnull);
+  do_check_eq(stmt->AsSharedWString(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(stmt->AsSharedBlob(0, &len), nsnull);
+  do_check_eq(stmt->AsSharedBlob(0, &len), NULL);
   do_check_eq(len, 0);
   do_check_eq(stmt->IsNull(0), true);
 
   do_check_eq(valueArray->AsInt32(0), 0);
   do_check_eq(valueArray->AsInt64(0), 0);
   do_check_eq(valueArray->AsDouble(0), 0.0);
   len = 100;
-  do_check_eq(valueArray->AsSharedUTF8String(0, &len), nsnull);
+  do_check_eq(valueArray->AsSharedUTF8String(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(valueArray->AsSharedWString(0, &len), nsnull);
+  do_check_eq(valueArray->AsSharedWString(0, &len), NULL);
   do_check_eq(len, 0);
   len = 100;
-  do_check_eq(valueArray->AsSharedBlob(0, &len), nsnull);
+  do_check_eq(valueArray->AsSharedBlob(0, &len), NULL);
   do_check_eq(len, 0);
   do_check_eq(valueArray->IsNull(0), true);
 }
 
 void
 test_asyncNULLFallback()
 {
   nsCOMPtr<mozIStorageConnection> db(getMemoryDatabase());

--- a/toolkit/components/places/nsNavBookmarks.cpp
+++ b/toolkit/components/places/nsNavBookmarks.cpp
@@ -587,17 +587,17 @@ nsNavBookmarks::InsertBookmark(PRInt64 a
 
   *aNewBookmarkId = -1;
   PRTime dateAdded = PR_Now();
   nsCAutoString guid;
   nsCString title;
   TruncateTitle(aTitle, title);
 
   rv = InsertBookmarkInDB(placeId, BOOKMARK, aFolder, index, title, dateAdded,
-                          nsnull, folderGuid, grandParentId, aURI,
+                          0, folderGuid, grandParentId, aURI,
                           aNewBookmarkId, guid);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // If not a tag, recalculate frecency for this entry, since it changed.
   if (grandParentId != mTagsRoot) {
     rv = history->UpdateFrecency(placeId);
     NS_ENSURE_SUCCESS(rv, rv);
   }
@@ -850,17 +850,17 @@ nsNavBookmarks::CreateContainerWithID(PR
 
   *aNewFolder = aItemId;
   PRTime dateAdded = PR_Now();
   nsCAutoString guid;
   nsCString title;
   TruncateTitle(aTitle, title);
 
   rv = InsertBookmarkInDB(-1, FOLDER, aParent, index,
-                          title, dateAdded, nsnull, folderGuid, grandParentId,
+                          title, dateAdded, 0, folderGuid, grandParentId,
                           nsnull, aNewFolder, guid);
   NS_ENSURE_SUCCESS(rv, rv);
 
   rv = transaction.Commit();
   NS_ENSURE_SUCCESS(rv, rv);
 
   NOTIFY_OBSERVERS(mCanNotify, mCacheObservers, mObservers,
                    nsINavBookmarkObserver,
@@ -903,17 +903,17 @@ nsNavBookmarks::InsertSeparator(PRInt64 
 
   *aNewItemId = -1;
   // Set a NULL title rather than an empty string.
   nsCString voidString;
   voidString.SetIsVoid(true);
   nsCAutoString guid;
   PRTime dateAdded = PR_Now();
   rv = InsertBookmarkInDB(-1, SEPARATOR, aParent, index, voidString, dateAdded,
-                          nsnull, folderGuid, grandParentId, nsnull,
+                          0, folderGuid, grandParentId, nsnull,
                           aNewItemId, guid);
   NS_ENSURE_SUCCESS(rv, rv);
 
   rv = transaction.Commit();
   NS_ENSURE_SUCCESS(rv, rv);
 
   NOTIFY_OBSERVERS(mCanNotify, mCacheObservers, mObservers,
                    nsINavBookmarkObserver,

--- a/widget/cocoa/TextInputHandler.mm
+++ b/widget/cocoa/TextInputHandler.mm
@@ -3103,17 +3103,17 @@ PluginTextInputHandler::ConvertUnicodeTo
                                                  unsigned char* aOutChar)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_RETURN;
 
   UnicodeToTextInfo converterInfo;
   TextEncoding      systemEncoding;
   Str255            convertedString;
 
-  *aOutChar = nsnull;
+  *aOutChar = '\0';
 
   OSStatus err =
     ::UpgradeScriptInfoToTextEncoding(smSystemScript,
                                       kTextLanguageDontCare,
                                       kTextRegionDontCare,
                                       NULL,
                                       &systemEncoding);
   NS_ENSURE_TRUE(err == noErr, false);

--- a/widget/xpwidgets/PuppetWidget.cpp
+++ b/widget/xpwidgets/PuppetWidget.cpp
@@ -199,17 +199,17 @@ PuppetWidget::SetFocus(bool aRaise)
   return NS_OK;
 }
 
 NS_IMETHODIMP
 PuppetWidget::Invalidate(const nsIntRect& aRect)
 {
 #ifdef DEBUG
   debug_DumpInvalidate(stderr, this, &aRect,
-                       nsCAutoString("PuppetWidget"), nsnull);
+                       nsCAutoString("PuppetWidget"), 0);
 #endif
 
   if (mChild) {
     return mChild->Invalidate(aRect);
   }
 
   mDirtyRegion.Or(mDirtyRegion, aRect);
 
@@ -236,17 +236,17 @@ PuppetWidget::InitEvent(nsGUIEvent& even
   event.time = PR_Now() / 1000;
 }
 
 NS_IMETHODIMP
 PuppetWidget::DispatchEvent(nsGUIEvent* event, nsEventStatus& aStatus)
 {
 #ifdef DEBUG
   debug_DumpEvent(stdout, event->widget, event,
-                  nsCAutoString("PuppetWidget"), nsnull);
+                  nsCAutoString("PuppetWidget"), 0);
 #endif
 
   NS_ABORT_IF_FALSE(!mChild || mChild->mWindowType == eWindowType_popup,
                     "Unexpected event dispatch!");
 
   aStatus = nsEventStatus_eIgnore;
 
   NS_ABORT_IF_FALSE(mViewCallback, "No view callback!");
@@ -490,17 +490,17 @@ PuppetWidget::DispatchPaintEvent()
   // reset repaint tracking
   mDirtyRegion.SetEmpty();
   mPaintTask.Revoke();
 
   nsEventStatus status;
   {
 #ifdef DEBUG
     debug_DumpPaintEvent(stderr, this, &event,
-                         nsCAutoString("PuppetWidget"), nsnull);
+                         nsCAutoString("PuppetWidget"), 0);
 #endif
 
     if (mozilla::layers::LAYERS_D3D10 == mLayerManager->GetBackendType()) {
       DispatchEvent(&event, status);
     } else {
       nsRefPtr<gfxContext> ctx = new gfxContext(mSurface);
       ctx->Rectangle(gfxRect(0,0,0,0));
       ctx->Clip();
@@ -564,17 +564,17 @@ PuppetWidget::GetDPI()
 }
 
 void*
 PuppetWidget::GetNativeData(PRUint32 aDataType)
 {
   switch (aDataType) {
   case NS_NATIVE_SHAREABLE_WINDOW: {
     NS_ABORT_IF_FALSE(mTabChild, "Need TabChild to get the nativeWindow from!");
-    mozilla::WindowsHandle nativeData = nsnull;
+    mozilla::WindowsHandle nativeData = 0;
     mTabChild->SendGetWidgetNativeData(&nativeData);
     return (void*)nativeData;
   }
   case NS_NATIVE_WINDOW:
   case NS_NATIVE_DISPLAY:
   case NS_NATIVE_PLUGIN_PORT:
   case NS_NATIVE_GRAPHIC:
   case NS_NATIVE_SHELLWIDGET:

--- a/xpcom/base/nscore.h
+++ b/xpcom/base/nscore.h
@@ -320,24 +320,28 @@ typedef PRUint32 nsresult;
  */
 #if defined(XP_WIN) && PR_BYTES_PER_LONG == 4
 typedef unsigned long nsrefcnt;
 #else
 typedef PRUint32 nsrefcnt;
 #endif
 
 /**
- * The preferred symbol for null.  Make sure this is the same size as
- * void* on the target.  See bug 547964.
+ * Use C++11 nullptr if available; otherwise use a C++ typesafe template; and
+ * for C, fall back to longs.  See bugs 547964 and 626472.
  */
+#ifndef HAVE_NULLPTR
 #if defined(_WIN64)
-# define nsnull 0LL
+# define nullptr 0LL
 #else
-# define nsnull 0L
+# define nullptr 0L
 #endif
+#endif /* defined(HAVE_NULLPTR) */
+
+#define nsnull nullptr
 
 
 #include "nsError.h"
 
 /* ------------------------------------------------------------------------ */
 /* Casting macros for hiding C++ features from older compilers */
 
   /* under VC++ (Windows), we don't have autoconf yet */

--- a/xpcom/glue/nsBaseHashtable.h
+++ b/xpcom/glue/nsBaseHashtable.h
@@ -120,17 +120,17 @@ public:
    * @return The found value, or nsnull if no entry was found with the given key.
    * @note If nsnull values are stored in the table, it is not possible to
    *       distinguish between a nsnull value and a missing entry.
    */
   UserDataType Get(KeyType aKey) const
   {
     EntryType* ent = this->GetEntry(aKey);
     if (!ent)
-      return nsnull;
+      return 0;
 
     return ent->mData;
   }
 
   /**
    * put a new value for the associated key
    * @param aKey the key to put
    * @param aData the new data

--- a/xpcom/glue/nsStringAPI.cpp
+++ b/xpcom/glue/nsStringAPI.cpp
@@ -263,33 +263,33 @@ nsAString::EqualsLiteral(const char *aAS
 
   for (; begin < end; ++begin, ++aASCIIString) {
     if (!*aASCIIString || !NS_IsAscii(*begin) ||
         (char) *begin != *aASCIIString) {
       return false;
     }
   }
 
-  return *aASCIIString == nsnull;
+  return *aASCIIString == '\0';
 }
 
 bool
 nsAString::LowerCaseEqualsLiteral(const char *aASCIIString) const
 {
   const PRUnichar *begin, *end;
   BeginReading(&begin, &end);
 
   for (; begin < end; ++begin, ++aASCIIString) {
     if (!*aASCIIString || !NS_IsAscii(*begin) ||
         NS_ToLower((char) *begin) != *aASCIIString) {
       return false;
     }
   }
 
-  return *aASCIIString == nsnull;
+  return *aASCIIString == '\0';
 }
 
 PRInt32
 nsAString::Find(const self_type& aStr, PRUint32 aOffset,
                 ComparatorFunc c) const
 {
   const char_type *begin, *end;
   PRUint32 selflen = BeginReading(&begin, &end);