merge to take src/core componentization into account

22 files changed, 80 insertions, 66 deletions

diff --git a/include/grpc++/generic/async_generic_service.h b/include/grpc++/generic/async_generic_service.h
index 9ae8391dc4..b87b17ee0d 100644
--- a/include/grpc++/generic/async_generic_service.h
+++ b/include/grpc++/generic/async_generic_service.h
@@ -34,8 +34,8 @@
 #ifndef GRPCXX_GENERIC_ASYNC_GENERIC_SERVICE_H
 #define GRPCXX_GENERIC_ASYNC_GENERIC_SERVICE_H
 
-#include <grpc++/support/byte_buffer.h>
 #include <grpc++/support/async_stream.h>
+#include <grpc++/support/byte_buffer.h>
 
 struct grpc_server;
 
diff --git a/include/grpc++/impl/codegen/async_stream.h b/include/grpc++/impl/codegen/async_stream.h
index 8f9afe8251..cac345e0dc 100644
--- a/include/grpc++/impl/codegen/async_stream.h
+++ b/include/grpc++/impl/codegen/async_stream.h
@@ -215,7 +215,8 @@ class ClientAsyncWriter GRPC_FINAL : public ClientAsyncWriterInterface<W> {
   CallOpSet<CallOpSendMessage> write_ops_;
   CallOpSet<CallOpClientSendClose> writes_done_ops_;
   CallOpSet<CallOpRecvInitialMetadata, CallOpGenericRecvMessage,
-            CallOpClientRecvStatus> finish_ops_;
+            CallOpClientRecvStatus>
+      finish_ops_;
 };
 
 /// Client-side interface for asynchronous bi-directional streaming.
@@ -350,7 +351,8 @@ class ServerAsyncReader GRPC_FINAL : public ServerAsyncStreamingInterface,
   CallOpSet<CallOpSendInitialMetadata> meta_ops_;
   CallOpSet<CallOpRecvMessage<R>> read_ops_;
   CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-            CallOpServerSendStatus> finish_ops_;
+            CallOpServerSendStatus>
+      finish_ops_;
 };
 
 template <class W>
diff --git a/include/grpc++/impl/codegen/async_unary_call.h b/include/grpc++/impl/codegen/async_unary_call.h
index 9c6dbd5484..1526debf54 100644
--- a/include/grpc++/impl/codegen/async_unary_call.h
+++ b/include/grpc++/impl/codegen/async_unary_call.h
@@ -101,10 +101,12 @@ class ClientAsyncResponseReader GRPC_FINAL
   class CallOpSetCollection : public CallOpSetCollectionInterface {
    public:
     SneakyCallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-                    CallOpClientSendClose> init_buf_;
+                    CallOpClientSendClose>
+        init_buf_;
     CallOpSet<CallOpRecvInitialMetadata> meta_buf_;
     CallOpSet<CallOpRecvInitialMetadata, CallOpRecvMessage<R>,
-              CallOpClientRecvStatus> finish_buf_;
+              CallOpClientRecvStatus>
+        finish_buf_;
   };
   std::shared_ptr<CallOpSetCollection> collection_;
 };
@@ -159,7 +161,8 @@ class ServerAsyncResponseWriter GRPC_FINAL
   ServerContext* ctx_;
   CallOpSet<CallOpSendInitialMetadata> meta_buf_;
   CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-            CallOpServerSendStatus> finish_buf_;
+            CallOpServerSendStatus>
+      finish_buf_;
 };
 
 }  // namespace grpc
diff --git a/include/grpc++/impl/codegen/call.h b/include/grpc++/impl/codegen/call.h
index 03affc2125..50f5a75191 100644
--- a/include/grpc++/impl/codegen/call.h
+++ b/include/grpc++/impl/codegen/call.h
@@ -280,7 +280,8 @@ class CallOpRecvMessage {
       if (*status) {
         got_message = true;
         *status = SerializationTraits<R>::Deserialize(recv_buf_, message_,
-                                                      max_message_size).ok();
+                                                      max_message_size)
+                      .ok();
       } else {
         got_message = false;
         g_core_codegen_interface->grpc_byte_buffer_destroy(recv_buf_);
diff --git a/include/grpc++/impl/codegen/client_unary_call.h b/include/grpc++/impl/codegen/client_unary_call.h
index a2b7d928c3..6c35a95765 100644
--- a/include/grpc++/impl/codegen/client_unary_call.h
+++ b/include/grpc++/impl/codegen/client_unary_call.h
@@ -56,7 +56,8 @@ Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,
   Call call(channel->CreateCall(method, context, &cq));
   CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
             CallOpRecvInitialMetadata, CallOpRecvMessage<OutputMessage>,
-            CallOpClientSendClose, CallOpClientRecvStatus> ops;
+            CallOpClientSendClose, CallOpClientRecvStatus>
+      ops;
   Status status = ops.SendMessage(request);
   if (!status.ok()) {
     return status;
diff --git a/include/grpc++/impl/codegen/impl/async_stream.h b/include/grpc++/impl/codegen/impl/async_stream.h
index 413eab7570..95c844723a 100644
--- a/include/grpc++/impl/codegen/impl/async_stream.h
+++ b/include/grpc++/impl/codegen/impl/async_stream.h
@@ -215,7 +215,8 @@ class ClientAsyncWriter GRPC_FINAL : public ClientAsyncWriterInterface<W> {
   CallOpSet<CallOpSendMessage> write_ops_;
   CallOpSet<CallOpClientSendClose> writes_done_ops_;
   CallOpSet<CallOpRecvInitialMetadata, CallOpGenericRecvMessage,
-            CallOpClientRecvStatus> finish_ops_;
+            CallOpClientRecvStatus>
+      finish_ops_;
 };
 
 /// Client-side interface for asynchronous bi-directional streaming.
@@ -350,7 +351,8 @@ class ServerAsyncReader GRPC_FINAL : public ServerAsyncStreamingInterface,
   CallOpSet<CallOpSendInitialMetadata> meta_ops_;
   CallOpSet<CallOpRecvMessage<R>> read_ops_;
   CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-            CallOpServerSendStatus> finish_ops_;
+            CallOpServerSendStatus>
+      finish_ops_;
 };
 
 template <class W>
diff --git a/include/grpc++/impl/codegen/method_handler_impl.h b/include/grpc++/impl/codegen/method_handler_impl.h
index 3ecca0a406..0ab2ae466a 100644
--- a/include/grpc++/impl/codegen/method_handler_impl.h
+++ b/include/grpc++/impl/codegen/method_handler_impl.h
@@ -61,7 +61,8 @@ class RpcMethodHandler : public MethodHandler {
 
     GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-              CallOpServerSendStatus> ops;
+              CallOpServerSendStatus>
+        ops;
     ops.SendInitialMetadata(param.server_context->initial_metadata_);
     if (status.ok()) {
       status = ops.SendMessage(rsp);
@@ -74,7 +75,8 @@ class RpcMethodHandler : public MethodHandler {
  private:
   // Application provided rpc handler function.
   std::function<Status(ServiceType*, ServerContext*, const RequestType*,
-                       ResponseType*)> func_;
+                       ResponseType*)>
+      func_;
   // The class the above handler function lives in.
   ServiceType* service_;
 };
@@ -96,7 +98,8 @@ class ClientStreamingHandler : public MethodHandler {
 
     GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-              CallOpServerSendStatus> ops;
+              CallOpServerSendStatus>
+        ops;
     ops.SendInitialMetadata(param.server_context->initial_metadata_);
     if (status.ok()) {
       status = ops.SendMessage(rsp);
@@ -108,7 +111,8 @@ class ClientStreamingHandler : public MethodHandler {
 
  private:
   std::function<Status(ServiceType*, ServerContext*, ServerReader<RequestType>*,
-                       ResponseType*)> func_;
+                       ResponseType*)>
+      func_;
   ServiceType* service_;
 };
 
@@ -143,7 +147,8 @@ class ServerStreamingHandler : public MethodHandler {
 
  private:
   std::function<Status(ServiceType*, ServerContext*, const RequestType*,
-                       ServerWriter<ResponseType>*)> func_;
+                       ServerWriter<ResponseType>*)>
+      func_;
   ServiceType* service_;
 };
 
@@ -174,7 +179,8 @@ class BidiStreamingHandler : public MethodHandler {
 
  private:
   std::function<Status(ServiceType*, ServerContext*,
-                       ServerReaderWriter<ResponseType, RequestType>*)> func_;
+                       ServerReaderWriter<ResponseType, RequestType>*)>
+      func_;
   ServiceType* service_;
 };
 
diff --git a/include/grpc++/impl/codegen/rpc_service_method.h b/include/grpc++/impl/codegen/rpc_service_method.h
index 6256301677..8b1f026c91 100644
--- a/include/grpc++/impl/codegen/rpc_service_method.h
+++ b/include/grpc++/impl/codegen/rpc_service_method.h
@@ -40,10 +40,10 @@
 #include <memory>
 #include <vector>
 
-#include <grpc/impl/codegen/byte_buffer.h>
 #include <grpc++/impl/codegen/config.h>
 #include <grpc++/impl/codegen/rpc_method.h>
 #include <grpc++/impl/codegen/status.h>
+#include <grpc/impl/codegen/byte_buffer.h>
 
 namespace grpc {
 class ServerContext;
diff --git a/include/grpc++/impl/codegen/server_context.h b/include/grpc++/impl/codegen/server_context.h
index 91ebe574b1..f8326bc44b 100644
--- a/include/grpc++/impl/codegen/server_context.h
+++ b/include/grpc++/impl/codegen/server_context.h
@@ -37,12 +37,12 @@
 #include <map>
 #include <memory>
 
-#include <grpc/impl/codegen/compression_types.h>
-#include <grpc/impl/codegen/time.h>
-#include <grpc++/impl/codegen/security/auth_context.h>
 #include <grpc++/impl/codegen/config.h>
+#include <grpc++/impl/codegen/security/auth_context.h>
 #include <grpc++/impl/codegen/string_ref.h>
 #include <grpc++/impl/codegen/time.h>
+#include <grpc/impl/codegen/compression_types.h>
+#include <grpc/impl/codegen/time.h>
 
 struct gpr_timespec;
 struct grpc_metadata;
diff --git a/include/grpc++/impl/codegen/server_interface.h b/include/grpc++/impl/codegen/server_interface.h
index 7d4ed277ed..908d124df1 100644
--- a/include/grpc++/impl/codegen/server_interface.h
+++ b/include/grpc++/impl/codegen/server_interface.h
@@ -192,10 +192,11 @@ class ServerInterface : public CallHook {
     bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
       bool serialization_status =
           *status && payload_ &&
-          SerializationTraits<Message>::Deserialize(
-              payload_, request_, server_->max_message_size()).ok();
+          SerializationTraits<Message>::Deserialize(payload_, request_,
+                                                    server_->max_message_size())
+              .ok();
       bool ret = RegisteredAsyncRequest::FinalizeResult(tag, status);
-      *status = serialization_status&&* status;
+      *status = serialization_status && *status;
       return ret;
     }
 
diff --git a/include/grpc++/impl/codegen/sync_stream.h b/include/grpc++/impl/codegen/sync_stream.h
index 5f878469ce..0eabc5fc0f 100644
--- a/include/grpc++/impl/codegen/sync_stream.h
+++ b/include/grpc++/impl/codegen/sync_stream.h
@@ -123,7 +123,8 @@ class ClientReader GRPC_FINAL : public ClientReaderInterface<R> {
                ClientContext* context, const W& request)
       : context_(context), call_(channel->CreateCall(method, context, &cq_)) {
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
-              CallOpClientSendClose> ops;
+              CallOpClientSendClose>
+        ops;
     ops.SendInitialMetadata(context->send_initial_metadata_);
     // TODO(ctiller): don't assert
     GPR_CODEGEN_ASSERT(ops.SendMessage(request).ok());
@@ -235,7 +236,8 @@ class ClientWriter : public ClientWriterInterface<W> {
  private:
   ClientContext* context_;
   CallOpSet<CallOpRecvInitialMetadata, CallOpGenericRecvMessage,
-            CallOpClientRecvStatus> finish_ops_;
+            CallOpClientRecvStatus>
+      finish_ops_;
   CompletionQueue cq_;
   Call call_;
 };
diff --git a/include/grpc++/support/byte_buffer.h b/include/grpc++/support/byte_buffer.h
index 27307f8fcd..3825518de1 100644
--- a/include/grpc++/support/byte_buffer.h
+++ b/include/grpc++/support/byte_buffer.h
@@ -34,13 +34,13 @@
 #ifndef GRPCXX_SUPPORT_BYTE_BUFFER_H
 #define GRPCXX_SUPPORT_BYTE_BUFFER_H
 
-#include <grpc/grpc.h>
-#include <grpc/byte_buffer.h>
-#include <grpc/support/log.h>
 #include <grpc++/impl/serialization_traits.h>
 #include <grpc++/support/config.h>
 #include <grpc++/support/slice.h>
 #include <grpc++/support/status.h>
+#include <grpc/byte_buffer.h>
+#include <grpc/grpc.h>
+#include <grpc/support/log.h>
 
 #include <vector>
 
diff --git a/include/grpc++/support/channel_arguments.h b/include/grpc++/support/channel_arguments.h
index a9ede35f90..8c2f7c71eb 100644
--- a/include/grpc++/support/channel_arguments.h
+++ b/include/grpc++/support/channel_arguments.h
@@ -34,12 +34,12 @@
 #ifndef GRPCXX_SUPPORT_CHANNEL_ARGUMENTS_H
 #define GRPCXX_SUPPORT_CHANNEL_ARGUMENTS_H
 
-#include <vector>
 #include <list>
+#include <vector>
 
+#include <grpc++/support/config.h>
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
-#include <grpc++/support/config.h>
 
 namespace grpc {
 namespace testing {
diff --git a/include/grpc++/support/slice.h b/include/grpc++/support/slice.h
index 724691a033..6251a8bcde 100644
--- a/include/grpc++/support/slice.h
+++ b/include/grpc++/support/slice.h
@@ -34,8 +34,8 @@
 #ifndef GRPCXX_SUPPORT_SLICE_H
 #define GRPCXX_SUPPORT_SLICE_H
 
-#include <grpc/support/slice.h>
 #include <grpc++/support/config.h>
+#include <grpc/support/slice.h>
 
 namespace grpc {
 
diff --git a/include/grpc/byte_buffer_reader.h b/include/grpc/byte_buffer_reader.h
index b0e63a6da2..600bd3810a 100644
--- a/include/grpc/byte_buffer_reader.h
+++ b/include/grpc/byte_buffer_reader.h
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -34,8 +34,8 @@
 #ifndef GRPC_BYTE_BUFFER_READER_H
 #define GRPC_BYTE_BUFFER_READER_H
 
-#include <grpc/grpc.h>
 #include <grpc/byte_buffer.h>
+#include <grpc/grpc.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/grpc/compression.h b/include/grpc/compression.h
index 70ba393261..39023ded34 100644
--- a/include/grpc/compression.h
+++ b/include/grpc/compression.h
@@ -36,8 +36,8 @@
 
 #include <stdlib.h>
 
-#include <grpc/impl/codegen/port_platform.h>
 #include <grpc/impl/codegen/compression_types.h>
+#include <grpc/impl/codegen/port_platform.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -59,9 +59,8 @@ GRPCAPI int grpc_compression_algorithm_name(
  * compression algorithms encoded in the \a accepted_encodings bitset.
  *
  * It abort()s for unknown levels . */
-GRPCAPI grpc_compression_algorithm
-grpc_compression_algorithm_for_level(grpc_compression_level level,
-                                     uint32_t accepted_encodings);
+GRPCAPI grpc_compression_algorithm grpc_compression_algorithm_for_level(
+    grpc_compression_level level, uint32_t accepted_encodings);
 
 GRPCAPI void grpc_compression_options_init(grpc_compression_options *opts);
 
diff --git a/include/grpc/grpc.h b/include/grpc/grpc.h
index 5113645daf..fe0cf28b3b 100644
--- a/include/grpc/grpc.h
+++ b/include/grpc/grpc.h
@@ -36,13 +36,13 @@
 
 #include <grpc/status.h>
 
-#include <stddef.h>
 #include <grpc/byte_buffer.h>
-#include <grpc/support/slice.h>
-#include <grpc/support/time.h>
 #include <grpc/impl/codegen/connectivity_state.h>
-#include <grpc/impl/codegen/propagation_bits.h>
 #include <grpc/impl/codegen/grpc_types.h>
+#include <grpc/impl/codegen/propagation_bits.h>
+#include <grpc/support/slice.h>
+#include <grpc/support/time.h>
+#include <stddef.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -154,9 +154,8 @@ GRPCAPI void grpc_alarm_cancel(grpc_alarm *alarm);
 GRPCAPI void grpc_alarm_destroy(grpc_alarm *alarm);
 
 /** Check the connectivity state of a channel. */
-GRPCAPI grpc_connectivity_state
-grpc_channel_check_connectivity_state(grpc_channel *channel,
-                                      int try_to_connect);
+GRPCAPI grpc_connectivity_state grpc_channel_check_connectivity_state(
+    grpc_channel *channel, int try_to_connect);
 
 /** Watch for a change in connectivity state.
     Once the channel connectivity state is different from last_observed_state,
@@ -267,9 +266,10 @@ GRPCAPI grpc_call_error grpc_call_cancel(grpc_call *call, void *reserved);
     and description passed in.
     Importantly, this function does not send status nor description to the
     remote endpoint. */
-GRPCAPI grpc_call_error
-grpc_call_cancel_with_status(grpc_call *call, grpc_status_code status,
-                             const char *description, void *reserved);
+GRPCAPI grpc_call_error grpc_call_cancel_with_status(grpc_call *call,
+                                                     grpc_status_code status,
+                                                     const char *description,
+                                                     void *reserved);
 
 /** Destroy a call.
     THREAD SAFETY: grpc_call_destroy is thread-compatible */
@@ -283,13 +283,11 @@ GRPCAPI void grpc_call_destroy(grpc_call *call);
     to \a cq_bound_to_call.
     Note that \a cq_for_notification must have been registered to the server via
     \a grpc_server_register_completion_queue. */
-GRPCAPI grpc_call_error
-grpc_server_request_call(grpc_server *server, grpc_call **call,
-                         grpc_call_details *details,
-                         grpc_metadata_array *request_metadata,
-                         grpc_completion_queue *cq_bound_to_call,
-                         grpc_completion_queue *cq_for_notification,
-                         void *tag_new);
+GRPCAPI grpc_call_error grpc_server_request_call(
+    grpc_server *server, grpc_call **call, grpc_call_details *details,
+    grpc_metadata_array *request_metadata,
+    grpc_completion_queue *cq_bound_to_call,
+    grpc_completion_queue *cq_for_notification, void *tag_new);
 
 /** Registers a method in the server.
     Methods to this (host, method) pair will not be reported by
diff --git a/include/grpc/grpc_security.h b/include/grpc/grpc_security.h
index 368d5dda51..f2d04e551a 100644
--- a/include/grpc/grpc_security.h
+++ b/include/grpc/grpc_security.h
@@ -80,9 +80,8 @@ grpc_auth_context_peer_identity(const grpc_auth_context *ctx);
 
 /* Finds a property in the context. May return an empty iterator (first _next
    will return NULL) if no property with this name was found in the context. */
-GRPCAPI grpc_auth_property_iterator
-grpc_auth_context_find_properties_by_name(const grpc_auth_context *ctx,
-                                          const char *name);
+GRPCAPI grpc_auth_property_iterator grpc_auth_context_find_properties_by_name(
+    const grpc_auth_context *ctx, const char *name);
 
 /* Gets the name of the property that indicates the peer identity. Will return
    NULL if the peer is not authenticated. */
@@ -363,8 +362,8 @@ GRPCAPI int grpc_server_add_secure_http2_port(grpc_server *server,
 
 /* Sets a credentials to a call. Can only be called on the client side before
    grpc_call_start_batch. */
-GRPCAPI grpc_call_error
-grpc_call_set_credentials(grpc_call *call, grpc_call_credentials *creds);
+GRPCAPI grpc_call_error grpc_call_set_credentials(grpc_call *call,
+                                                  grpc_call_credentials *creds);
 
 /* --- Auth Metadata Processing --- */
 
diff --git a/include/grpc/impl/codegen/log.h b/include/grpc/impl/codegen/log.h
index d6e18e9ca5..afd8c5d4cf 100644
--- a/include/grpc/impl/codegen/log.h
+++ b/include/grpc/impl/codegen/log.h
@@ -34,8 +34,8 @@
 #ifndef GRPC_IMPL_CODEGEN_LOG_H
 #define GRPC_IMPL_CODEGEN_LOG_H
 
-#include <stdlib.h> /* for abort() */
 #include <stdarg.h>
+#include <stdlib.h> /* for abort() */
 
 #include <grpc/impl/codegen/port_platform.h>
 
diff --git a/include/grpc/impl/codegen/slice.h b/include/grpc/impl/codegen/slice.h
index a62fdd087b..03c59e72a0 100644
--- a/include/grpc/impl/codegen/slice.h
+++ b/include/grpc/impl/codegen/slice.h
@@ -122,8 +122,8 @@ GPRAPI gpr_slice gpr_slice_new(void *p, size_t len, void (*destroy)(void *));
 
 /* Equivalent to gpr_slice_new, but with a two argument destroy function that
    also takes the slice length. */
-GPRAPI gpr_slice
-gpr_slice_new_with_len(void *p, size_t len, void (*destroy)(void *, size_t));
+GPRAPI gpr_slice gpr_slice_new_with_len(void *p, size_t len,
+                                        void (*destroy)(void *, size_t));
 
 /* Equivalent to gpr_slice_new(malloc(len), len, free), but saves one malloc()
    call.
diff --git a/include/grpc/impl/codegen/slice_buffer.h b/include/grpc/impl/codegen/slice_buffer.h
index 4fe909ee82..7191878496 100644
--- a/include/grpc/impl/codegen/slice_buffer.h
+++ b/include/grpc/impl/codegen/slice_buffer.h
@@ -73,8 +73,8 @@ GPRAPI void gpr_slice_buffer_add(gpr_slice_buffer *sb, gpr_slice slice);
    slice at the returned index in sb->slices)
    The implementation MAY decide to concatenate data at the end of a small
    slice added in this fashion. */
-GPRAPI size_t
-gpr_slice_buffer_add_indexed(gpr_slice_buffer *sb, gpr_slice slice);
+GPRAPI size_t gpr_slice_buffer_add_indexed(gpr_slice_buffer *sb,
+                                           gpr_slice slice);
 GPRAPI void gpr_slice_buffer_addn(gpr_slice_buffer *sb, gpr_slice *slices,
                                   size_t n);
 /* add a very small (less than 8 bytes) amount of data to the end of a slice
diff --git a/include/grpc/impl/codegen/time.h b/include/grpc/impl/codegen/time.h
index c22bedfe77..b4f45097c7 100644
--- a/include/grpc/impl/codegen/time.h
+++ b/include/grpc/impl/codegen/time.h
@@ -88,8 +88,8 @@ GPRAPI void gpr_time_init(void);
 GPRAPI gpr_timespec gpr_now(gpr_clock_type clock);
 
 /* Convert a timespec from one clock to another */
-GPRAPI gpr_timespec
-gpr_convert_clock_type(gpr_timespec t, gpr_clock_type target_clock);
+GPRAPI gpr_timespec gpr_convert_clock_type(gpr_timespec t,
+                                           gpr_clock_type target_clock);
 
 /* Return -ve, 0, or +ve according to whether a < b, a == b, or a > b
    respectively.  */