Start better error reporting for sockets

runtime/bin/dartutils.h

 // Copyright (c) 2012, 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 BIN_DARTUTILS_H_
 #define BIN_DARTUTILS_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 #include "include/dart_api.h"
@@ skipping 147 matching lines @@
   static Dart_CObject* NewString(const char* str);
   static Dart_CObject* NewArray(int length);
   static Dart_CObject* NewByteArray(int length);
 
   Dart_CObject* AsApiCObject() { return cobject_; }
 
   // Create a new CObject array with an illegal arguments error.
   static CObject* IllegalArgumentError();
   // Create a new CObject array with the current OS error.
   static CObject* NewOSError();
+  // Create a new CObject array with the specified OS error.
+  static CObject* NewOSError(OSError* os_error);
 
  protected:
   CObject() : cobject_(NULL) {}
   Dart_CObject* cobject_;
 
  private:
   static Dart_CObject* New(Dart_CObject::Type type, int additional_bytes = 0);
 
   static Dart_CObject api_null_;
   static Dart_CObject api_true_;
@@ skipping 106 matching lines @@
 
 class CObjectByteArray : public CObject {
  public:
   DECLARE_COBJECT_CONSTRUCTORS(ByteArray)
 
   int Length() const { return cobject_->value.as_byte_array.length; }
   uint8_t* Buffer() const { return cobject_->value.as_byte_array.values; }
 };
 
 #endif  // BIN_DARTUTILS_H_