mirror of
https://github.com/wpilibsuite/allwpilib
synced 2026-06-20 00:51:42 +00:00
a73166a665
Moving these headers from src to include enables other libraries to use the functionality provided. * tcpsockets * atomic_static * raw_istream * timestamp * SafeThread * Base64 * LEB128 * ConcurrentQueue The classes have been moved into the wpi namespace as they're generic.
50 lines
1.8 KiB
C++
50 lines
1.8 KiB
C++
/*----------------------------------------------------------------------------*/
|
|
/* Copyright (c) FIRST 2015. All Rights Reserved. */
|
|
/* Open Source Software - may be modified and shared by FRC teams. The code */
|
|
/* must be accompanied by the FIRST BSD license file in the root directory of */
|
|
/* the project. */
|
|
/*----------------------------------------------------------------------------*/
|
|
|
|
#ifndef WPIUTIL_SUPPORT_ATOMIC_STATIC_H_
|
|
#define WPIUTIL_SUPPORT_ATOMIC_STATIC_H_
|
|
|
|
#if !defined(_MSC_VER) || (_MSC_VER >= 1900)
|
|
|
|
// Just use a local static. This is thread-safe per
|
|
// http://preshing.com/20130930/double-checked-locking-is-fixed-in-cpp11/
|
|
|
|
// Per https://msdn.microsoft.com/en-us/library/Hh567368.aspx "Magic Statics"
|
|
// are supported in Visual Studio 2015 but not in earlier versions.
|
|
#define ATOMIC_STATIC(cls, inst) static cls inst
|
|
#define ATOMIC_STATIC_DECL(cls)
|
|
#define ATOMIC_STATIC_INIT(cls)
|
|
|
|
#else
|
|
// From http://preshing.com/20130930/double-checked-locking-is-fixed-in-cpp11/
|
|
#include <atomic>
|
|
#include <mutex>
|
|
|
|
#define ATOMIC_STATIC(cls, inst) \
|
|
cls* inst##tmp = m_instance.load(std::memory_order_acquire); \
|
|
if (inst##tmp == nullptr) { \
|
|
std::lock_guard<std::mutex> lock(m_instance_mutex); \
|
|
inst##tmp = m_instance.load(std::memory_order_relaxed); \
|
|
if (inst##tmp == nullptr) { \
|
|
inst##tmp = new cls; \
|
|
m_instance.store(inst##tmp, std::memory_order_release); \
|
|
} \
|
|
} \
|
|
cls& inst = *inst##tmp
|
|
|
|
#define ATOMIC_STATIC_DECL(cls) \
|
|
static std::atomic<cls*> m_instance; \
|
|
static std::mutex m_instance_mutex;
|
|
|
|
#define ATOMIC_STATIC_INIT(cls) \
|
|
std::atomic<cls*> cls::m_instance; \
|
|
std::mutex cls::m_instance_mutex;
|
|
|
|
#endif
|
|
|
|
#endif // WPIUTIL_SUPPORT_ATOMIC_STATIC_H_
|