null_mutex.h
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// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
#pragma once
#include <atomic>
#include <utility>
// null, no cost dummy "mutex" and dummy "atomic" int
namespace spdlog {
namespace details {
struct null_mutex
{
void lock() const {}
void unlock() const {}
bool try_lock() const
{
return true;
}
};
struct null_atomic_int
{
int value;
null_atomic_int() = default;
explicit null_atomic_int(int new_value)
: value(new_value)
{}
int load(std::memory_order = std::memory_order_relaxed) const
{
return value;
}
void store(int new_value, std::memory_order = std::memory_order_relaxed)
{
value = new_value;
}
int exchange(int new_value, std::memory_order = std::memory_order_relaxed)
{
std::swap(new_value, value);
return new_value; // return value before the call
}
};
} // namespace details
} // namespace spdlog