Minor tweaks to API documentation and code comments.

mojo/public/c/system/functions.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains basic functions common to different Mojo system APIs.
 //
 // Note: This header should be compilable as C.
 
 #ifndef MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_
 #define MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_
 
-// Note: This header should be compilable as C.
-
 #include "mojo/public/c/system/system_export.h"
 #include "mojo/public/c/system/types.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 // Note: Pointer parameters that are labelled "optional" may be null (at least
 // under some circumstances). Non-const pointer parameters are also labeled
 // "in", "out", or "in/out", to indicate how they are used. (Note that how/if
 // such a parameter is used may depend on other parameters or the requested
 // operation's success/failure. E.g., a separate |flags| parameter may control
 // whether a given "in/out" parameter is used for input, output, or both.)
 
-// Platform-dependent monotonically increasing tick count representing "right
-// now." The resolution of this clock is ~1-15ms. Resolution varies depending
-// on hardware/operating system configuration.
+// Returns the time, in microseconds, since some undefined point in the past.
+// The values are only meaningful relative to other values that were obtained
+// from the same device without an intervening system restart.  Such values are

[viettrungluu, 2015/01/30 23:45:42]

nit: one space after '.'

[ggowan, 2015/01/31 00:44:15]

Done.

+// guaranteed to be monotonically-increasing with the passage of real time.
+// Although the units are microseconds, the resolution of the clock may vary and
+// is typically in the range of ~1-15 ms.
 MOJO_SYSTEM_EXPORT MojoTimeTicks MojoGetTimeTicksNow(void);
 
 // Closes the given |handle|.
 //
 // Returns:
 //   |MOJO_RESULT_OK| on success.
 //   |MOJO_RESULT_INVALID_ARGUMENT| if |handle| is not a valid handle.
 //
 // Concurrent operations on |handle| may succeed (or fail as usual) if they
 // happen before the close, be cancelled with result |MOJO_RESULT_CANCELLED| if
@@ skipping 23 matching lines @@
 //       thread) during the wait.
 //   |MOJO_RESULT_INVALID_ARGUMENT| if |handle| is not a valid handle (e.g., if
 //       it has already been closed). The |signals_state| value is unchanged.
 //   |MOJO_RESULT_DEADLINE_EXCEEDED| if the deadline has passed without any of
 //       the signals being satisfied.
 //   |MOJO_RESULT_FAILED_PRECONDITION| if it becomes known that none of the
 //       signals in |signals| can ever be satisfied (e.g., when waiting on one
 //       end of a message pipe and the other end is closed).
 //
 // If there are multiple waiters (on different threads, obviously) waiting on
-// the same handle and signal, and that signal becomes is satisfied, all waiters
+// the same handle and signal, and that signal becomes satisfied, all waiters
 // will be awoken.
 MOJO_SYSTEM_EXPORT MojoResult
 MojoWait(MojoHandle handle,
          MojoHandleSignals signals,
          MojoDeadline deadline,
          struct MojoHandleSignalsState* signals_state);  // Optional out.
 
 // Waits on |handles[0]|, ..., |handles[num_handles-1]| until:
 //   - (At least) one handle satisfies a signal indicated in its respective
 //     |signals[0]|, ..., |signals[num_handles-1]|.
@@ skipping 39 matching lines @@
              uint32_t num_handles,
              MojoDeadline deadline,
              uint32_t* result_index,                          // Optional out
              struct MojoHandleSignalsState* signals_states);  // Optional out
 
 #ifdef __cplusplus
 }  // extern "C"
 #endif
 
 #endif  // MOJO_PUBLIC_C_SYSTEM_FUNCTIONS_H_