Fix gRPC ObjC void function definition

src/objective-c/GRPCClient/GRPCCall.m

@@ -296,7 +296,7 @@ static NSString * const kBearerPrefix = @"Bearer ";
 // network queue if the write didn't succeed.
 // If the call is a unary call, parameter \a errorHandler will be ignored and
 // the error handler of GRPCOpSendClose will be executed in case of error.
-- (void)writeMessage:(NSData *)message withErrorHandler:(void (^)())errorHandler {
+- (void)writeMessage:(NSData *)message withErrorHandler:(void (^)(void))errorHandler {
 
   __weak GRPCCall *weakSelf = self;
   void(^resumingHandler)(void) = ^{
@@ -342,7 +342,7 @@ static NSString * const kBearerPrefix = @"Bearer ";
 
 // Only called from the call queue. The error handler will be called from the
 // network queue if the requests stream couldn't be closed successfully.
-- (void)finishRequestWithErrorHandler:(void (^)())errorHandler {
+- (void)finishRequestWithErrorHandler:(void (^)(void))errorHandler {
   if (!_unaryCall) {
     [_wrappedCall startBatchWithOperations:@[[[GRPCOpSendClose alloc] init]]
                               errorHandler:errorHandler];
@@ -438,7 +438,7 @@ static NSString * const kBearerPrefix = @"Bearer ";
   }
   _connectivityMonitor = [GRPCConnectivityMonitor monitorWithHost:host];
   __weak typeof(self) weakSelf = self;
-  void (^handler)() = ^{
+  void (^handler)(void) = ^{
     typeof(self) strongSelf = weakSelf;
     [strongSelf finishWithError:[NSError errorWithDomain:kGRPCErrorDomain
                                                     code:GRPCErrorCodeUnavailable

src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.h

@@ -57,6 +57,6 @@
  * Only one handler is active at a time, so if this method is called again before the previous
  * handler has been called, it might never be called at all (or yes, if it has already been queued).
  */
-- (void)handleLossWithHandler:(nullable void (^)())lossHandler
-      wifiStatusChangeHandler:(nullable void (^)())wifiStatusChangeHandler;
+- (void)handleLossWithHandler:(nullable void (^)(void))lossHandler
+      wifiStatusChangeHandler:(nullable void (^)(void))wifiStatusChangeHandler;
 @end

src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m

@@ -136,8 +136,8 @@ static void PassFlagsToContextInfoBlock(SCNetworkReachabilityRef target,
   return returnValue;
 }
 
-- (void)handleLossWithHandler:(nullable void (^)())lossHandler
-      wifiStatusChangeHandler:(nullable void (^)())wifiStatusChangeHandler {
+- (void)handleLossWithHandler:(nullable void (^)(void))lossHandler
+      wifiStatusChangeHandler:(nullable void (^)(void))wifiStatusChangeHandler {
   __weak typeof(self) weakSelf = self;
   [self startListeningWithHandler:^(GRPCReachabilityFlags *flags) {
     typeof(self) strongSelf = weakSelf;

src/objective-c/GRPCClient/private/GRPCHost.m

@@ -93,7 +93,7 @@ static GRPCConnectivityMonitor *connectivityMonitor = nil;
     if (!connectivityMonitor) {
       connectivityMonitor =
       [GRPCConnectivityMonitor monitorWithHost:hostURL.host];
-      void (^handler)() = ^{
+      void (^handler)(void) = ^{
         [GRPCHost flushChannelCache];
       };
       [connectivityMonitor handleLossWithHandler:handler

src/objective-c/GRPCClient/private/GRPCWrappedCall.h

@@ -30,24 +30,24 @@
 @interface GRPCOpSendMetadata : GRPCOperation
 
 - (instancetype)initWithMetadata:(NSDictionary *)metadata
-                         handler:(void(^)())handler;
+                         handler:(void(^)(void))handler;
 
 - (instancetype)initWithMetadata:(NSDictionary *)metadata
                            flags:(uint32_t)flags
-                         handler:(void(^)())handler NS_DESIGNATED_INITIALIZER;
+                         handler:(void(^)(void))handler NS_DESIGNATED_INITIALIZER;
 
 @end
 
 @interface GRPCOpSendMessage : GRPCOperation
 
 - (instancetype)initWithMessage:(NSData *)message
-                        handler:(void(^)())handler NS_DESIGNATED_INITIALIZER;
+                        handler:(void(^)(void))handler NS_DESIGNATED_INITIALIZER;
 
 @end
 
 @interface GRPCOpSendClose : GRPCOperation
 
-- (instancetype)initWithHandler:(void(^)())handler NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithHandler:(void(^)(void))handler NS_DESIGNATED_INITIALIZER;
 
 @end
 
@@ -79,7 +79,7 @@
                         path:(NSString *)path
                      timeout:(NSTimeInterval)timeout NS_DESIGNATED_INITIALIZER;
 
-- (void)startBatchWithOperations:(NSArray *)ops errorHandler:(void(^)())errorHandler;
+- (void)startBatchWithOperations:(NSArray *)ops errorHandler:(void(^)(void))errorHandler;
 
 - (void)startBatchWithOperations:(NSArray *)ops;
 

src/objective-c/GRPCClient/private/GRPCWrappedCall.m

@@ -36,12 +36,12 @@
   // Most operation subclasses don't set any flags in the grpc_op, and rely on the flag member being
   // initialized to zero.
   grpc_op _op;
-  void(^_handler)();
+  void(^_handler)(void);
 }
 
 - (void)finish {
   if (_handler) {
-    void(^handler)() = _handler;
+    void(^handler)(void) = _handler;
     _handler = nil;
     handler();
   }
@@ -55,13 +55,13 @@
 }
 
 - (instancetype)initWithMetadata:(NSDictionary *)metadata
-                         handler:(void (^)())handler {
+                         handler:(void (^)(void))handler {
   return [self initWithMetadata:metadata flags:0 handler:handler];
 }
 
 - (instancetype)initWithMetadata:(NSDictionary *)metadata
                            flags:(uint32_t)flags
-                         handler:(void (^)())handler {
+                         handler:(void (^)(void))handler {
   if (self = [super init]) {
     _op.op = GRPC_OP_SEND_INITIAL_METADATA;
     _op.data.send_initial_metadata.count = metadata.count;
@@ -92,7 +92,7 @@
   return [self initWithMessage:nil handler:nil];
 }
 
-- (instancetype)initWithMessage:(NSData *)message handler:(void (^)())handler {
+- (instancetype)initWithMessage:(NSData *)message handler:(void (^)(void))handler {
   if (!message) {
     [NSException raise:NSInvalidArgumentException format:@"message cannot be nil"];
   }
@@ -116,7 +116,7 @@
   return [self initWithHandler:nil];
 }
 
-- (instancetype)initWithHandler:(void (^)())handler {
+- (instancetype)initWithHandler:(void (^)(void))handler {
   if (self = [super init]) {
     _op.op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
     _handler = handler;
@@ -271,7 +271,7 @@
   [self startBatchWithOperations:operations errorHandler:nil];
 }
 
-- (void)startBatchWithOperations:(NSArray *)operations errorHandler:(void (^)())errorHandler {
+- (void)startBatchWithOperations:(NSArray *)operations errorHandler:(void (^)(void))errorHandler {
   // Keep logs of op batches when we are running tests. Disabled when in production for improved
   // performance.
 #ifdef GRPC_TEST_OBJC

src/objective-c/RxLibrary/GRXConcurrentWriteable.h

@@ -46,7 +46,7 @@
  * Enqueues writeValue: to be sent to the writeable in the main thread.
  * The passed handler is invoked from the main thread after writeValue: returns.
  */
-- (void)enqueueValue:(id)value completionHandler:(void (^)())handler;
+- (void)enqueueValue:(id)value completionHandler:(void (^)(void))handler;
 
 /**
  * Enqueues writesFinishedWithError:nil to be sent to the writeable in the main thread. After that

src/objective-c/RxLibrary/GRXConcurrentWriteable.m

@@ -50,7 +50,7 @@
                    dispatchQueue:dispatch_get_main_queue()];
 }
 
-- (void)enqueueValue:(id)value completionHandler:(void (^)())handler {
+- (void)enqueueValue:(id)value completionHandler:(void (^)(void))handler {
   dispatch_async(_writeableQueue, ^{
     // We're racing a possible cancellation performed by another thread. To turn all already-
     // enqueued messages into noops, cancellation nillifies the writeable property. If we get it

src/objective-c/RxLibrary/GRXImmediateWriter.h

@@ -46,7 +46,7 @@
  * Returns a writer that pushes to its writeable the successive values returned by the passed
  * block. When the block first returns nil, it is released.
  */
-+ (GRXWriter *)writerWithValueSupplier:(id (^)())block;
++ (GRXWriter *)writerWithValueSupplier:(id (^)(void))block;
 
 /**
  * Returns a writer that iterates over the values of the passed container and pushes them to

src/objective-c/RxLibrary/GRXImmediateWriter.m

@@ -52,7 +52,7 @@
   return [self writerWithEnumerator:enumerator error:nil];
 }
 
-+ (GRXWriter *)writerWithValueSupplier:(id (^)())block {
++ (GRXWriter *)writerWithValueSupplier:(id (^)(void))block {
   return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithValueSupplier:block]];
 }
 

src/objective-c/RxLibrary/GRXWriter+Immediate.h

@@ -30,7 +30,7 @@
  * Returns a writer that pushes to its writeable the successive values returned by the passed
  * block. When the block first returns nil, it is released.
  */
-+ (instancetype)writerWithValueSupplier:(id (^)())block;
++ (instancetype)writerWithValueSupplier:(id (^)(void))block;
 
 /**
  * Returns a writer that iterates over the values of the passed container and pushes them to

src/objective-c/RxLibrary/GRXWriter+Immediate.m

@@ -27,7 +27,7 @@
   return [GRXImmediateWriter writerWithEnumerator:enumerator];
 }
 
-+ (instancetype)writerWithValueSupplier:(id (^)())block {
++ (instancetype)writerWithValueSupplier:(id (^)(void))block {
   return [GRXImmediateWriter writerWithValueSupplier:block];
 }
 

src/objective-c/RxLibrary/NSEnumerator+GRXUtil.h

@@ -38,5 +38,5 @@
  * Returns a NSEnumerator instance that delegates the invocations of nextObject to the passed block.
  * When the block first returns nil, it is released.
  */
-+ (NSEnumerator *)grx_enumeratorWithValueSupplier:(id (^)())block;
++ (NSEnumerator *)grx_enumeratorWithValueSupplier:(id (^)(void))block;
 @end

src/objective-c/RxLibrary/NSEnumerator+GRXUtil.m

@@ -33,7 +33,7 @@
   return [[GRXNSScalarEnumerator alloc] initWithValue:value];
 }
 
-+ (NSEnumerator *)grx_enumeratorWithValueSupplier:(id (^)())block {
++ (NSEnumerator *)grx_enumeratorWithValueSupplier:(id (^)(void))block {
   return [[GRXNSBlockEnumerator alloc] initWithValueSupplier:block];
 }
 @end

src/objective-c/RxLibrary/private/GRXNSBlockEnumerator.h

@@ -27,5 +27,5 @@
  * The first time the passed block returns nil, the enumeration will end and the block will be
  * released.
  */
-- (instancetype)initWithValueSupplier:(id (^)())block;
+- (instancetype)initWithValueSupplier:(id (^)(void))block;
 @end

src/objective-c/RxLibrary/private/GRXNSBlockEnumerator.m

@@ -19,14 +19,14 @@
 #import "GRXNSBlockEnumerator.h"
 
 @implementation GRXNSBlockEnumerator {
-  id (^_block)();
+  id (^_block)(void);
 }
 
 - (instancetype)init {
   return [self initWithValueSupplier:nil];
 }
 
-- (instancetype)initWithValueSupplier:(id (^)())block {
+- (instancetype)initWithValueSupplier:(id (^)(void))block {
   if ((self = [super init])) {
     _block = block;
   }