bdlm_instancecount.h

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/// @file bdlm_instancecount.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdlm_instancecount.h                                               -*-C++-*-
#ifndef INCLUDED_BDLM_INSTANCECOUNT
#define INCLUDED_BDLM_INSTANCECOUNT
 
/// @defgroup bdlm_instancecount bdlm_instancecount
/// @brief  Provide a type specific instance count.
/// @addtogroup bdl
/// @{
/// @addtogroup bdlm
/// @{
/// @addtogroup bdlm_instancecount
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdlm_instancecount-purpose"> Purpose</a>
/// * <a href="#bdlm_instancecount-classes"> Classes </a>
/// * <a href="#bdlm_instancecount-description"> Description </a>
///   * <a href="#bdlm_instancecount-thread-safety"> Thread Safety </a>
///   * <a href="#bdlm_instancecount-usage"> Usage </a>
///     * <a href="#bdlm_instancecount-example-1-using-bdlm-instancecount"> Example 1: Using bdlm::InstanceCount </a>
///
/// # Purpose {#bdlm_instancecount-purpose}
/// Provide a type specific instance count.
///
/// # Classes {#bdlm_instancecount-classes}
///
/// - bdlm::InstanceCount: type specific instance count
///
/// # Description {#bdlm_instancecount-description}
/// This component provides a mechanism, `bdlm::InstanceCount`, for
/// providing type specific instance counts.
///
/// ## Thread Safety {#bdlm_instancecount-thread-safety}
///
///
/// This class is *fully thread-safe*
/// (see {@ref bsldoc_glossary |Fully Thread-Safe}).
///
/// ## Usage {#bdlm_instancecount-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Using bdlm::InstanceCount {#bdlm_instancecount-example-1-using-bdlm-instancecount}
///
///
/// This example demonstrates the usage of `bdlm::InstanceCount` to obtain type
/// specific instance counts.
///
/// First, we obtain and verify the instance counts for a few types:
/// @code
/// assert(1 == bdlm::InstanceCount::nextInstanceNumber<char>());
/// assert(1 == bdlm::InstanceCount::nextInstanceNumber<int>());
/// assert(1 == bdlm::InstanceCount::nextInstanceNumber<double>());
/// @endcode
/// Then, we obtain and verify the instance counts for the previous types and
/// some new types:
/// @code
/// assert(2 == bdlm::InstanceCount::nextInstanceNumber<char>());
/// assert(2 == bdlm::InstanceCount::nextInstanceNumber<int>());
/// assert(1 == bdlm::InstanceCount::nextInstanceNumber<unsigned>());
/// assert(1 == bdlm::InstanceCount::nextInstanceNumber<float>());
/// assert(2 == bdlm::InstanceCount::nextInstanceNumber<double>());
/// @endcode
/// Finally, we obtain and verify the next instance counts for these types:
/// @code
/// assert(3 == bdlm::InstanceCount::nextInstanceNumber<char>());
/// assert(3 == bdlm::InstanceCount::nextInstanceNumber<int>());
/// assert(2 == bdlm::InstanceCount::nextInstanceNumber<unsigned>());
/// assert(2 == bdlm::InstanceCount::nextInstanceNumber<float>());
/// assert(3 == bdlm::InstanceCount::nextInstanceNumber<double>());
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdlm
 * @{
 */
/** @addtogroup bdlm_instancecount
 * @{
 */
 
#include <bsls_ident.h>
BSLS_IDENT("$Id$")
 
#include <bsls_atomicoperations.h>
#include <bsls_types.h>
 
 
namespace bdlm {
 
                           // ===================
                           // class InstanceCount
                           // ===================
 
/// This mechanism provides type specific instance counts.
///
/// See @ref bdlm_instancecount 
struct InstanceCount {
 
    // TYPES
    typedef bsls::Types::Uint64 Value;  // storage type for instance counts
 
    // CLASS METHODS
 
    /// Return the next instance number for the specified `OBJECT_TYPE`.
    template <class OBJECT_TYPE>
    static Value nextInstanceNumber();
};
 
// ============================================================================
//                             INLINE DEFINITIONS
// ============================================================================
 
                           // -------------------
                           // class InstanceCount
                           // -------------------
 
// CLASS METHODS
template <class OBJECT_TYPE>
inline
InstanceCount::Value InstanceCount::nextInstanceNumber()
{
    static bsls::AtomicOperations::AtomicTypes::Uint64 count;
    return bsls::AtomicOperations::incrementUint64Nv(&count);
}
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2024 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */