互斥對象鎖和臨界區鎖性能比較

在Win32平台上進行多線程編程，常會用到鎖。下邊用C++實現了互斥對象（Mutex）鎖和臨界區（CRITICAL_SECTION）鎖，以加深理解和今後方便使用。代碼已在VS2005環境下編譯測試通過。

Lock.h

1. #ifndef _Lock_H
2. #define _Lock_H
4. #include <windows.h>
7. //鎖接口類
8. class ILock
9. {
10. public:
11. virtual ~ILock() {}
13. virtual void Lock() const = 0;
14. virtual void Unlock() const = 0;
15. };
17. //互斥對象鎖類
18. class Mutex : public ILock
19. {
20. public:
21. Mutex();
22. ~Mutex();
24. virtual void Lock() const;
25. virtual void Unlock() const;
27. private:
28. HANDLE m_mutex;
29. };
31. //臨界區鎖類
32. class CriSection : public ILock
33. {
34. public:
35. CriSection();
36. ~CriSection();
38. virtual void Lock() const;
39. virtual void Unlock() const;
41. private:
42. CRITICAL_SECTION m_critclSection;
43. };
46. //鎖
47. class CMyLock
48. {
49. public:
50. CMyLock(const ILock&);
51. ~CMyLock();
53. private:
54. const ILock& m_lock;
55. };
58. #endif

Lock.cpp

1. #include "Lock.h"
3. //---------------------------------------------------------------------------
5. //創建一個匿名互斥對象
6. Mutex::Mutex()
7. {
8. m_mutex = ::CreateMutex(NULL, FALSE, NULL);
9. }
11. //銷毀互斥對象，釋放資源
12. Mutex::~Mutex()
13. {
14. ::CloseHandle(m_mutex);
15. }
17. //確保擁有互斥對象的線程對被保護資源的獨自訪問
18. void Mutex::Lock() const
19. {
20. DWORD d = WaitForSingleObject(m_mutex, INFINITE);
21. }
23. //釋放當前線程擁有的互斥對象，以使其它線程可以擁有互斥對象，對被保護資源進行訪問
24. void Mutex::Unlock() const
25. {
26. ::ReleaseMutex(m_mutex);
27. }
29. //---------------------------------------------------------------------------
31. //初始化臨界資源對象
32. CriSection::CriSection()
33. {
34. ::InitializeCriticalSection(&m_critclSection);
35. }
37. //釋放臨界資源對象
38. CriSection::~CriSection()
39. {
40. ::DeleteCriticalSection(&m_critclSection);
41. }
43. //進入臨界區，加鎖
44. void CriSection::Lock() const
45. {
46. ::EnterCriticalSection((LPCRITICAL_SECTION)&m_critclSection);
47. }
49. //離開臨界區，解鎖
50. void CriSection::Unlock() const
51. {
52. ::LeaveCriticalSection((LPCRITICAL_SECTION)&m_critclSection);
53. }
55. //---------------------------------------------------------------------------
57. //利用C++特性，進行自動加鎖
58. CMyLock::CMyLock(const ILock& m) : m_lock(m)
59. {
60. m_lock.Lock();
61. }
63. //利用C++特性，進行自動解鎖
64. CMyLock::~CMyLock()
65. {
66. m_lock.Unlock();
67. }