diff --git a/cpp/src/slice2objc/Gen.cpp b/cpp/src/slice2objc/Gen.cpp
index c52ea9bbf17..3923e3fabaf 100644
--- a/cpp/src/slice2objc/Gen.cpp
+++ b/cpp/src/slice2objc/Gen.cpp
@@ -3106,23 +3106,14 @@ Slice::Gen::DelegateMVisitor::visitOperation(const OperationPtr& p)
         if(returnType)
         {
             _M << nl << outTypeToString(returnType, p->returnIsOptional(), true) << " ret";
-            if(!isValueType(returnType))
-            {
-                _M << " = nil;";
-            }
-            else
-            {
-                _M << ";";
-            }
+            _M << " = " << defaultValue(returnType, p->returnIsOptional()) << ";";
         }
         if(p->returnsData())
         {
             for(ParamDeclList::const_iterator op = outParams.begin(); op != outParams.end(); ++op)
             {
-                if(!isValueType((*op)->type()))
-                {
-                    _M << nl << "*" << getParamName(*op, true) << " = nil;";
-                }
+                _M << nl << "*" << getParamName(*op, true) << " = " << defaultValue((*op)->type(), (*op)->optional())
+                   << ";";
             }
         }
         _M << nl << "if(!ok)";
diff --git a/cpp/src/slice2objc/ObjCUtil.cpp b/cpp/src/slice2objc/ObjCUtil.cpp
index 1848cbcbf4d..cf7e34fd5f0 100644
--- a/cpp/src/slice2objc/ObjCUtil.cpp
+++ b/cpp/src/slice2objc/ObjCUtil.cpp
@@ -427,6 +427,46 @@ Slice::ObjCGenerator::typeToObjCTypeString(const TypePtr& type)
     }
 }
 
+string
+Slice::ObjCGenerator::defaultValue(const TypePtr& type, bool isOptional)
+{
+    if(isValueType(type) && !isOptional)
+    {
+         if(EnumPtr::dynamicCast(type))
+         {
+             return "0";
+         }
+         BuiltinPtr builtin = BuiltinPtr::dynamicCast(type);
+         if(builtin)
+         {
+             switch(builtin->kind())
+             {
+             case Builtin::KindBool:
+                 return "NO";
+             case Builtin::KindByte:
+             case Builtin::KindShort:
+             case Builtin::KindInt:
+             case Builtin::KindLong:
+                 return "0";
+             case Builtin::KindFloat:
+             case Builtin::KindDouble:
+                 return "0.0";
+             default:
+                 {
+                     assert(false);
+                     return "???";
+                 }
+             }
+         }
+         assert(false);
+         return "???";
+    }
+    else
+    {
+        return "nil";
+    }
+}
+
 bool
 Slice::ObjCGenerator::isValueType(const TypePtr& type)
 {
diff --git a/cpp/src/slice2objc/ObjCUtil.h b/cpp/src/slice2objc/ObjCUtil.h
index 0c5176d67d8..4520ee7082a 100644
--- a/cpp/src/slice2objc/ObjCUtil.h
+++ b/cpp/src/slice2objc/ObjCUtil.h
@@ -52,6 +52,7 @@ class ObjCGenerator : private ::IceUtil::noncopyable
     static std::string inTypeToString(const TypePtr&, bool, bool = false, bool = false);
     static std::string outTypeToString(const TypePtr&, bool, bool = false, bool = false);
     static std::string typeToObjCTypeString(const TypePtr&);
+    static std::string defaultValue(const TypePtr&, bool);
     static bool isValueType(const TypePtr&);
     static bool isString(const TypePtr&);
     static bool isClass(const TypePtr&);
diff --git a/objective-c/test/Ice/defaultValue/Client.m b/objective-c/test/Ice/defaultValue/Client.m
index bc36e6977ee..9983d7030c0 100644
--- a/objective-c/test/Ice/defaultValue/Client.m
+++ b/objective-c/test/Ice/defaultValue/Client.m
@@ -7,7 +7,7 @@
 #import <DefaultValueTest.h>
 
 static int
-run()
+run(void)
 {
     void defaultValueAllTests(void);
     defaultValueAllTests();
diff --git a/objective-c/test/Ice/dispatcher/AllTests.m b/objective-c/test/Ice/dispatcher/AllTests.m
index f237c0492c8..a46e22f6414 100644
--- a/objective-c/test/Ice/dispatcher/AllTests.m
+++ b/objective-c/test/Ice/dispatcher/AllTests.m
@@ -8,7 +8,7 @@
 
 #import <Foundation/Foundation.h>
 
-static BOOL isDispatcherThread()
+static BOOL isDispatcherThread(void)
 {
     return strcmp(dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL), "Dispatcher") == 0;
 }
diff --git a/objective-c/test/Ice/hash/Client.m b/objective-c/test/Ice/hash/Client.m
index 867593665b6..e942196b4f3 100644
--- a/objective-c/test/Ice/hash/Client.m
+++ b/objective-c/test/Ice/hash/Client.m
@@ -7,7 +7,7 @@
 #import <HashTest.h>
 
 static int
-run()
+run(void)
 {
     void hashAllTests(void);
     hashAllTests();
diff --git a/objective-c/test/Ice/services/AllTests.m b/objective-c/test/Ice/services/AllTests.m
index 44102d01730..11d47dab75a 100644
--- a/objective-c/test/Ice/services/AllTests.m
+++ b/objective-c/test/Ice/services/AllTests.m
@@ -50,8 +50,8 @@ -(void)tick:(NSString*)time current:(ICECurrent*)__unused current
         ICESTORMTopicManagerPrx* manager =
                     [ICESTORMTopicManagerPrx uncheckedCast:[communicator stringToProxy:@"test:default -p 12010"]];
 
-        ICESTORMQoS* qos;
-        ICESTORMTopicPrx* topic;
+        ICESTORMQoS* qos = nil;
+        ICESTORMTopicPrx* topic = nil;
         NSString* topicName = @"time";
 
         id<ICEObjectAdapter> adapter = [communicator createObjectAdapterWithEndpoints:@"subscriber" endpoints:@"tcp"];
diff --git a/objective-c/test/Slice/escape/Client.m b/objective-c/test/Slice/escape/Client.m
index bc18968677e..805c417dfd6 100644
--- a/objective-c/test/Slice/escape/Client.m
+++ b/objective-c/test/Slice/escape/Client.m
@@ -29,7 +29,7 @@ @interface andfriendI : ICELocalObject<andfriend>
 // are named correctly. It is not expected to run.
 //
 static void
-testSymbols()
+testSymbols(void)
 {
     andbreakPrx* prx1  = 0;
     [prx1 case_:0 try:0];