ClickHouse/contrib/libpoco/Foundation/include/Poco/Void.h

76 lines
1.3 KiB
C++

//
// Void.h
//
// $Id: //poco/1.4/Foundation/include/Poco/Void.h#1 $
//
// Library: Foundation
// Package: Core
// Module: Void
//
// Definition of the Void class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_Void_INCLUDED
#define Foundation_Void_INCLUDED
#include "Poco/Foundation.h"
namespace Poco {
class Foundation_API Void
/// A dummy class with value-type semantics,
/// mostly useful as a template argument.
///
/// This class is typically used together with ActiveMethod,
/// if no argument or return value is needed.
{
public:
Void();
/// Creates the Void.
Void(const Void& v);
/// Creates the Void from another Void.
///
/// The philosophical aspects of this operation
/// remain undiscussed for now.
~Void();
/// Destroys the Void.
Void& operator = (const Void& v);
/// Assigns another void.
bool operator ==(const Void& v) const;
/// Will return always true due to Voids having no members.
bool operator !=(const Void& v) const;
/// Will return always false due to Voids having no members.
};
inline bool Void::operator ==(const Void& /*v*/) const
{
return true;
}
inline bool Void::operator !=(const Void& /*v*/) const
{
return false;
}
} // namespace Poco
#endif // Foundation_Void_INCLUDED