includes/prometheus/gauge.h

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/*
 * SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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.
 */
 
#pragma once
 
#include <atomic>
 
#include "prometheus/client_metric.h"
#include "prometheus/detail/builder.h"  // IWYU pragma: export
#include "prometheus/detail/core_export.h"
#include "prometheus/metric_type.h"
 
namespace prometheus {
 
class PROMETHEUS_CPP_CORE_EXPORT Gauge {
 public:
  static const MetricType metric_type{MetricType::Gauge};
 
  Gauge() = default;
 
  explicit Gauge(double);
 
  void Increment();
 
  void Increment(double);
 
  void Decrement();
 
  void Decrement(double);
 
  void Set(double);
 
  void SetToCurrentTime();
 
  double Value() const;
 
  ClientMetric Collect() const;
 
 private:
  void Change(double);
  std::atomic<double> value_{0.0};
};
 
PROMETHEUS_CPP_CORE_EXPORT detail::Builder<Gauge> BuildGauge();
 
}  // namespace prometheus