Error checking for Stdio calls

runtime/bin/stdio.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_BIN_STDIO_H_
 #define RUNTIME_BIN_STDIO_H_
 
 #if defined(DART_IO_DISABLED)
 #error "stdio.h can only be included on builds with IO enabled"
 #endif
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
 #include "platform/globals.h"
 
 namespace dart {
 namespace bin {
 
 class Stdin {
  public:
-  static int ReadByte();
+  static bool ReadByte(int* byte);
 
-  static bool GetEchoMode();
-  static void SetEchoMode(bool enabled);
+  static bool GetEchoMode(bool* enabled);
+  static bool SetEchoMode(bool enabled);
 
-  static bool GetLineMode();
-  static void SetLineMode(bool enabled);
+  static bool GetLineMode(bool* enabled);
+  static bool SetLineMode(bool enabled);
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Stdin);
 };
 
 
 class Stdout {
  public:
   static bool GetTerminalSize(intptr_t fd, int size[2]);
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Stdout);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // RUNTIME_BIN_STDIO_H_