diff --git a/src/mac/carbon/settings.cpp b/src/mac/carbon/settings.cpp
index 5c3cc0990b..dcfab47793 100644
--- a/src/mac/carbon/settings.cpp
+++ b/src/mac/carbon/settings.cpp
@@ -151,13 +151,16 @@ wxFont wxSystemSettingsNative::GetFont(wxSystemFont index)
 // Get a system metric, e.g. scrollbar size
 int wxSystemSettingsNative::GetMetric(wxSystemMetric index)
 {
+    int value;
+
     switch ( index)
     {
         case wxSYS_MOUSE_BUTTONS:
-                    return 2; // we emulate a two button mouse (ctrl + click = right button )
+            // we emulate a two button mouse (ctrl + click = right button )
+            return 2;
         case wxSYS_BORDER_X:
             // TODO
-                    return 0;
+            return 0;
         case wxSYS_BORDER_Y:
             // TODO
             return 0;
@@ -210,11 +213,11 @@ int wxSystemSettingsNative::GetMetric(wxSystemMetric index)
             // TODO
             return 0;
         case wxSYS_SCREEN_X:
-            // TODO
-            return 0;
+            wxDisplaySize(&value, NULL);
+            return value;
         case wxSYS_SCREEN_Y:
-            // TODO
-            return 0;
+            wxDisplaySize(NULL, &value);
+            return value;
         case wxSYS_FRAMESIZE_X:
             // TODO
             return 0;
diff --git a/src/mac/carbon/utils.cpp b/src/mac/carbon/utils.cpp
index ad685519dd..4e31d12476 100644
--- a/src/mac/carbon/utils.cpp
+++ b/src/mac/carbon/utils.cpp
@@ -450,11 +450,15 @@ int wxDisplayDepth()
 // Get size of display
 void wxDisplaySize(int *width, int *height)
 {
-  	BitMap screenBits;
-  	GetQDGlobalsScreenBits( &screenBits );
+    BitMap screenBits;
+    GetQDGlobalsScreenBits( &screenBits );
 
-    *width = screenBits.bounds.right - screenBits.bounds.left  ;
-    *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    if (width != NULL) {
+        *width = screenBits.bounds.right - screenBits.bounds.left  ;
+    }
+    if (height != NULL) {
+        *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    }
 }
 
 void wxDisplaySizeMM(int *width, int *height)
@@ -462,29 +466,42 @@ void wxDisplaySizeMM(int *width, int *height)
     wxDisplaySize(width, height);
     // on mac 72 is fixed (at least now ;-)
     float cvPt2Mm = 25.4 / 72;
-    *width = int( *width * cvPt2Mm );
-    *height = int( *height * cvPt2Mm );
+
+    if (width != NULL) {
+        *width = int( *width * cvPt2Mm );
+    }
+    if (height != NULL) {
+        *height = int( *height * cvPt2Mm );
+    }
 }
 
 void wxClientDisplayRect(int *x, int *y, int *width, int *height)
 {
-  	BitMap screenBits;
-  	GetQDGlobalsScreenBits( &screenBits );
+    BitMap screenBits;
+    GetQDGlobalsScreenBits( &screenBits );
 
-    if (x) *x = 0;
-    if (y) *y = 0;
+    if (x)
+        *x = 0;
+    if (y)
+        *y = 0;
 
-    *width = screenBits.bounds.right - screenBits.bounds.left  ;
-    *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    if (width != NULL) {
+        *width = screenBits.bounds.right - screenBits.bounds.left  ;
+    }
+    if (height != NULL) {
+        *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    }
 
-   	SInt16 mheight ;
+    SInt16 mheight ;
   #if TARGET_CARBON
-   	GetThemeMenuBarHeight( &mheight ) ;
+    GetThemeMenuBarHeight( &mheight ) ;
   #else
     mheight = LMGetMBarHeight() ;
   #endif
-    *height -= mheight ;
-    if ( y )
+    if (height != NULL) {
+        *height -= mheight ;
+    }
+    if (y)
       *y = mheight ;
 }
 
diff --git a/src/mac/settings.cpp b/src/mac/settings.cpp
index 5c3cc0990b..dcfab47793 100644
--- a/src/mac/settings.cpp
+++ b/src/mac/settings.cpp
@@ -151,13 +151,16 @@ wxFont wxSystemSettingsNative::GetFont(wxSystemFont index)
 // Get a system metric, e.g. scrollbar size
 int wxSystemSettingsNative::GetMetric(wxSystemMetric index)
 {
+    int value;
+
     switch ( index)
     {
         case wxSYS_MOUSE_BUTTONS:
-                    return 2; // we emulate a two button mouse (ctrl + click = right button )
+            // we emulate a two button mouse (ctrl + click = right button )
+            return 2;
         case wxSYS_BORDER_X:
             // TODO
-                    return 0;
+            return 0;
         case wxSYS_BORDER_Y:
             // TODO
             return 0;
@@ -210,11 +213,11 @@ int wxSystemSettingsNative::GetMetric(wxSystemMetric index)
             // TODO
             return 0;
         case wxSYS_SCREEN_X:
-            // TODO
-            return 0;
+            wxDisplaySize(&value, NULL);
+            return value;
         case wxSYS_SCREEN_Y:
-            // TODO
-            return 0;
+            wxDisplaySize(NULL, &value);
+            return value;
         case wxSYS_FRAMESIZE_X:
             // TODO
             return 0;
diff --git a/src/mac/utils.cpp b/src/mac/utils.cpp
index ad685519dd..4e31d12476 100644
--- a/src/mac/utils.cpp
+++ b/src/mac/utils.cpp
@@ -450,11 +450,15 @@ int wxDisplayDepth()
 // Get size of display
 void wxDisplaySize(int *width, int *height)
 {
-  	BitMap screenBits;
-  	GetQDGlobalsScreenBits( &screenBits );
+    BitMap screenBits;
+    GetQDGlobalsScreenBits( &screenBits );
 
-    *width = screenBits.bounds.right - screenBits.bounds.left  ;
-    *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    if (width != NULL) {
+        *width = screenBits.bounds.right - screenBits.bounds.left  ;
+    }
+    if (height != NULL) {
+        *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    }
 }
 
 void wxDisplaySizeMM(int *width, int *height)
@@ -462,29 +466,42 @@ void wxDisplaySizeMM(int *width, int *height)
     wxDisplaySize(width, height);
     // on mac 72 is fixed (at least now ;-)
     float cvPt2Mm = 25.4 / 72;
-    *width = int( *width * cvPt2Mm );
-    *height = int( *height * cvPt2Mm );
+
+    if (width != NULL) {
+        *width = int( *width * cvPt2Mm );
+    }
+    if (height != NULL) {
+        *height = int( *height * cvPt2Mm );
+    }
 }
 
 void wxClientDisplayRect(int *x, int *y, int *width, int *height)
 {
-  	BitMap screenBits;
-  	GetQDGlobalsScreenBits( &screenBits );
+    BitMap screenBits;
+    GetQDGlobalsScreenBits( &screenBits );
 
-    if (x) *x = 0;
-    if (y) *y = 0;
+    if (x)
+        *x = 0;
+    if (y)
+        *y = 0;
 
-    *width = screenBits.bounds.right - screenBits.bounds.left  ;
-    *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    if (width != NULL) {
+        *width = screenBits.bounds.right - screenBits.bounds.left  ;
+    }
+    if (height != NULL) {
+        *height = screenBits.bounds.bottom - screenBits.bounds.top ;
+    }
 
-   	SInt16 mheight ;
+    SInt16 mheight ;
   #if TARGET_CARBON
-   	GetThemeMenuBarHeight( &mheight ) ;
+    GetThemeMenuBarHeight( &mheight ) ;
   #else
     mheight = LMGetMBarHeight() ;
   #endif
-    *height -= mheight ;
-    if ( y )
+    if (height != NULL) {
+        *height -= mheight ;
+    }
+    if (y)
       *y = mheight ;
 }