annotate_smart_pointer.cpp revision e32f8626804ace131a11b074784f335af71e2299
1e32f8626804ace131a11b074784f335af71e2299bart/* 2e32f8626804ace131a11b074784f335af71e2299bart * Test program that illustrates how to annotate a smart pointer 3e32f8626804ace131a11b074784f335af71e2299bart * implementation. In a multithreaded program the following is relevant when 4e32f8626804ace131a11b074784f335af71e2299bart * working with smart pointers: 5e32f8626804ace131a11b074784f335af71e2299bart * - whether or not the objects pointed at are shared over threads. 6e32f8626804ace131a11b074784f335af71e2299bart * - whether or not the methods of the objects pointed at are thread-safe. 7e32f8626804ace131a11b074784f335af71e2299bart * - whether or not the smart pointer objects are shared over threads. 8e32f8626804ace131a11b074784f335af71e2299bart * - whether or not the smart pointer object itself is thread-safe. 9e32f8626804ace131a11b074784f335af71e2299bart * 10e32f8626804ace131a11b074784f335af71e2299bart * Most smart pointer implemenations are not thread-safe 11e32f8626804ace131a11b074784f335af71e2299bart * (e.g. boost::shared_ptr<>, tr1::shared_ptr<> and the smart_ptr<> 12e32f8626804ace131a11b074784f335af71e2299bart * implementation below). This means that it is not safe to modify a shared 13e32f8626804ace131a11b074784f335af71e2299bart * pointer object that is shared over threads without proper synchronization. 14e32f8626804ace131a11b074784f335af71e2299bart * 15e32f8626804ace131a11b074784f335af71e2299bart * Even for non-thread-safe smart pointers it is possible to have different 16e32f8626804ace131a11b074784f335af71e2299bart * threads access the same object via smart pointers without triggering data 17e32f8626804ace131a11b074784f335af71e2299bart * races on the smart pointer objects. 18e32f8626804ace131a11b074784f335af71e2299bart * 19e32f8626804ace131a11b074784f335af71e2299bart * A smart pointer implementation guarantees that the destructor of the object 20e32f8626804ace131a11b074784f335af71e2299bart * pointed at is invoked after the last smart pointer that points to that 21e32f8626804ace131a11b074784f335af71e2299bart * object has been destroyed or reset. Data race detection tools cannot detect 22e32f8626804ace131a11b074784f335af71e2299bart * this ordering without explicit annotation for smart pointers that track 23e32f8626804ace131a11b074784f335af71e2299bart * references without invoking synchronization operations recognized by data 24e32f8626804ace131a11b074784f335af71e2299bart * race detection tools. 25e32f8626804ace131a11b074784f335af71e2299bart */ 26e32f8626804ace131a11b074784f335af71e2299bart 27e32f8626804ace131a11b074784f335af71e2299bart 28e32f8626804ace131a11b074784f335af71e2299bart#include <cassert> // assert() 29e32f8626804ace131a11b074784f335af71e2299bart#include <climits> // PTHREAD_STACK_MIN 30e32f8626804ace131a11b074784f335af71e2299bart#include <iostream> // std::cout 31e32f8626804ace131a11b074784f335af71e2299bart#include <stdlib.h> // atoi() 32c710de6053e28508b4d49065f50bf10e4861b508bart#ifdef _WIN32 33e32f8626804ace131a11b074784f335af71e2299bart#include <process.h> // _beginthreadex() 34e32f8626804ace131a11b074784f335af71e2299bart#include <windows.h> // CRITICAL_SECTION 35c710de6053e28508b4d49065f50bf10e4861b508bart#else 36e32f8626804ace131a11b074784f335af71e2299bart#include <pthread.h> // pthread_mutex_t 37c710de6053e28508b4d49065f50bf10e4861b508bart#endif 38e32f8626804ace131a11b074784f335af71e2299bart#include "../../drd/drd.h" 39e32f8626804ace131a11b074784f335af71e2299bart 40c710de6053e28508b4d49065f50bf10e4861b508bart 41c710de6053e28508b4d49065f50bf10e4861b508bart#ifdef _WIN32 42e32f8626804ace131a11b074784f335af71e2299bart 43c710de6053e28508b4d49065f50bf10e4861b508bartclass AtomicInt32 44c710de6053e28508b4d49065f50bf10e4861b508bart{ 45c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 46c710de6053e28508b4d49065f50bf10e4861b508bart AtomicInt32(const int value = 0) : m_value(value) { } 47c710de6053e28508b4d49065f50bf10e4861b508bart ~AtomicInt32() { } 48c710de6053e28508b4d49065f50bf10e4861b508bart LONG operator++() { return InterlockedIncrement(&m_value); } 49c710de6053e28508b4d49065f50bf10e4861b508bart LONG operator--() { return InterlockedDecrement(&m_value); } 50c710de6053e28508b4d49065f50bf10e4861b508bart 51c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 52c710de6053e28508b4d49065f50bf10e4861b508bart volatile LONG m_value; 53c710de6053e28508b4d49065f50bf10e4861b508bart}; 54c710de6053e28508b4d49065f50bf10e4861b508bart 55c710de6053e28508b4d49065f50bf10e4861b508bartclass Mutex 56c710de6053e28508b4d49065f50bf10e4861b508bart{ 57c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 58c710de6053e28508b4d49065f50bf10e4861b508bart Mutex() : m_mutex() 59c710de6053e28508b4d49065f50bf10e4861b508bart { InitializeCriticalSection(&m_mutex); } 60c710de6053e28508b4d49065f50bf10e4861b508bart ~Mutex() 61c710de6053e28508b4d49065f50bf10e4861b508bart { DeleteCriticalSection(&m_mutex); } 62c710de6053e28508b4d49065f50bf10e4861b508bart void Lock() 63c710de6053e28508b4d49065f50bf10e4861b508bart { EnterCriticalSection(&m_mutex); } 64c710de6053e28508b4d49065f50bf10e4861b508bart void Unlock() 65c710de6053e28508b4d49065f50bf10e4861b508bart { LeaveCriticalSection(&m_mutex); } 66c710de6053e28508b4d49065f50bf10e4861b508bart 67c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 68c710de6053e28508b4d49065f50bf10e4861b508bart CRITICAL_SECTION m_mutex; 69c710de6053e28508b4d49065f50bf10e4861b508bart}; 70c710de6053e28508b4d49065f50bf10e4861b508bart 71c710de6053e28508b4d49065f50bf10e4861b508bartclass Thread 72c710de6053e28508b4d49065f50bf10e4861b508bart{ 73c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 74c710de6053e28508b4d49065f50bf10e4861b508bart Thread() : m_thread(INVALID_HANDLE_VALUE) { } 75c710de6053e28508b4d49065f50bf10e4861b508bart ~Thread() { } 76c710de6053e28508b4d49065f50bf10e4861b508bart void Create(void* (*pf)(void*), void* arg) 77c710de6053e28508b4d49065f50bf10e4861b508bart { 78e32f8626804ace131a11b074784f335af71e2299bart WrapperArgs* wrapper_arg_p = new WrapperArgs(pf, arg); 79e32f8626804ace131a11b074784f335af71e2299bart m_thread = reinterpret_cast<HANDLE>(_beginthreadex(NULL, 0, wrapper, 80e32f8626804ace131a11b074784f335af71e2299bart wrapper_arg_p, 0, NULL)); 81c710de6053e28508b4d49065f50bf10e4861b508bart } 82c710de6053e28508b4d49065f50bf10e4861b508bart void Join() 83c710de6053e28508b4d49065f50bf10e4861b508bart { WaitForSingleObject(m_thread, INFINITE); } 84c710de6053e28508b4d49065f50bf10e4861b508bart 85c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 86e32f8626804ace131a11b074784f335af71e2299bart struct WrapperArgs 87c710de6053e28508b4d49065f50bf10e4861b508bart { 88e32f8626804ace131a11b074784f335af71e2299bart WrapperArgs(void* (*pf)(void*), void* arg) : m_pf(pf), m_arg(arg) { } 89c710de6053e28508b4d49065f50bf10e4861b508bart 90c710de6053e28508b4d49065f50bf10e4861b508bart void* (*m_pf)(void*); 91c710de6053e28508b4d49065f50bf10e4861b508bart void* m_arg; 92c710de6053e28508b4d49065f50bf10e4861b508bart }; 93c710de6053e28508b4d49065f50bf10e4861b508bart static unsigned int __stdcall wrapper(void* arg) 94c710de6053e28508b4d49065f50bf10e4861b508bart { 95e32f8626804ace131a11b074784f335af71e2299bart WrapperArgs* wrapper_arg_p = reinterpret_cast<WrapperArgs*>(arg); 96e32f8626804ace131a11b074784f335af71e2299bart WrapperArgs wa = *wrapper_arg_p; 97c710de6053e28508b4d49065f50bf10e4861b508bart delete wrapper_arg_p; 98c710de6053e28508b4d49065f50bf10e4861b508bart return reinterpret_cast<unsigned>((wa.m_pf)(wa.m_arg)); 99c710de6053e28508b4d49065f50bf10e4861b508bart } 100c710de6053e28508b4d49065f50bf10e4861b508bart HANDLE m_thread; 101c710de6053e28508b4d49065f50bf10e4861b508bart}; 102e32f8626804ace131a11b074784f335af71e2299bart 103c710de6053e28508b4d49065f50bf10e4861b508bart#else // _WIN32 104e32f8626804ace131a11b074784f335af71e2299bart 105c710de6053e28508b4d49065f50bf10e4861b508bartclass AtomicInt32 106c710de6053e28508b4d49065f50bf10e4861b508bart{ 107c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 108c710de6053e28508b4d49065f50bf10e4861b508bart AtomicInt32(const int value = 0) : m_value(value) { } 109c710de6053e28508b4d49065f50bf10e4861b508bart ~AtomicInt32() { } 110c710de6053e28508b4d49065f50bf10e4861b508bart int operator++() { return __sync_add_and_fetch(&m_value, 1); } 111c710de6053e28508b4d49065f50bf10e4861b508bart int operator--() { return __sync_sub_and_fetch(&m_value, 1); } 112c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 113c710de6053e28508b4d49065f50bf10e4861b508bart volatile int m_value; 114c710de6053e28508b4d49065f50bf10e4861b508bart}; 115c710de6053e28508b4d49065f50bf10e4861b508bart 116c710de6053e28508b4d49065f50bf10e4861b508bartclass Mutex 117c710de6053e28508b4d49065f50bf10e4861b508bart{ 118c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 119c710de6053e28508b4d49065f50bf10e4861b508bart Mutex() : m_mutex() 120c710de6053e28508b4d49065f50bf10e4861b508bart { pthread_mutex_init(&m_mutex, NULL); } 121c710de6053e28508b4d49065f50bf10e4861b508bart ~Mutex() 122c710de6053e28508b4d49065f50bf10e4861b508bart { pthread_mutex_destroy(&m_mutex); } 123c710de6053e28508b4d49065f50bf10e4861b508bart void Lock() 124c710de6053e28508b4d49065f50bf10e4861b508bart { pthread_mutex_lock(&m_mutex); } 125c710de6053e28508b4d49065f50bf10e4861b508bart void Unlock() 126c710de6053e28508b4d49065f50bf10e4861b508bart { pthread_mutex_unlock(&m_mutex); } 127c710de6053e28508b4d49065f50bf10e4861b508bart 128c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 129c710de6053e28508b4d49065f50bf10e4861b508bart pthread_mutex_t m_mutex; 130c710de6053e28508b4d49065f50bf10e4861b508bart}; 131c710de6053e28508b4d49065f50bf10e4861b508bart 132c710de6053e28508b4d49065f50bf10e4861b508bartclass Thread 133c710de6053e28508b4d49065f50bf10e4861b508bart{ 134c710de6053e28508b4d49065f50bf10e4861b508bartpublic: 135c710de6053e28508b4d49065f50bf10e4861b508bart Thread() : m_tid() { } 136c710de6053e28508b4d49065f50bf10e4861b508bart ~Thread() { } 137c710de6053e28508b4d49065f50bf10e4861b508bart void Create(void* (*pf)(void*), void* arg) 138e32f8626804ace131a11b074784f335af71e2299bart { 139e32f8626804ace131a11b074784f335af71e2299bart pthread_attr_t attr; 140e32f8626804ace131a11b074784f335af71e2299bart pthread_attr_init(&attr); 141e32f8626804ace131a11b074784f335af71e2299bart pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN + 4096); 142e32f8626804ace131a11b074784f335af71e2299bart pthread_create(&m_tid, &attr, pf, arg); 143e32f8626804ace131a11b074784f335af71e2299bart pthread_attr_destroy(&attr); 144e32f8626804ace131a11b074784f335af71e2299bart } 145c710de6053e28508b4d49065f50bf10e4861b508bart void Join() 146c710de6053e28508b4d49065f50bf10e4861b508bart { pthread_join(m_tid, NULL); } 147c710de6053e28508b4d49065f50bf10e4861b508bartprivate: 148c710de6053e28508b4d49065f50bf10e4861b508bart pthread_t m_tid; 149c710de6053e28508b4d49065f50bf10e4861b508bart}; 150e32f8626804ace131a11b074784f335af71e2299bart 151e32f8626804ace131a11b074784f335af71e2299bart#endif // !defined(_WIN32) 152c710de6053e28508b4d49065f50bf10e4861b508bart 15321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 15421e49d778a698f3e28ba2ad6b3b0430a26f9255ebarttemplate<class T> 15521e49d778a698f3e28ba2ad6b3b0430a26f9255ebartclass smart_ptr 15621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart{ 15721e49d778a698f3e28ba2ad6b3b0430a26f9255ebartpublic: 158c710de6053e28508b4d49065f50bf10e4861b508bart typedef AtomicInt32 counter_t; 15921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 16021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart template <typename Q> friend class smart_ptr; 16121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 16221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart explicit smart_ptr() 16321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_ptr(NULL), m_count_ptr(NULL) 16421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { } 16521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 16621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart explicit smart_ptr(T* const pT) 16721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_ptr(NULL), m_count_ptr(NULL) 16821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 16921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(pT, pT ? new counter_t(0) : NULL); 17021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 17121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 17221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart template <typename Q> 17321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart explicit smart_ptr(Q* const q) 17421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_ptr(NULL), m_count_ptr(NULL) 17521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 17621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(q, q ? new counter_t(0) : NULL); 17721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 17821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 17921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart ~smart_ptr() 18021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 18121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(NULL, NULL); 18221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 18321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 18421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr(const smart_ptr<T>& sp) 18521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_ptr(NULL), m_count_ptr(NULL) 18621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 18721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(sp.m_ptr, sp.m_count_ptr); 18821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 18921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 19021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart template <typename Q> 19121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr(const smart_ptr<Q>& sp) 19221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_ptr(NULL), m_count_ptr(NULL) 19321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 19421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(sp.m_ptr, sp.m_count_ptr); 19521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 19621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 19721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr& operator=(const smart_ptr<T>& sp) 19821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 19921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(sp.m_ptr, sp.m_count_ptr); 20021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return *this; 20121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 20221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 20321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr& operator=(T* const p) 20421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 20521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(p, p ? new counter_t(0) : NULL); 20621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return *this; 20721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 20821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 20921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart template <typename Q> 21021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr& operator=(Q* const q) 21121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 21221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart set(q, q ? new counter_t(0) : NULL); 21321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return *this; 21421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 21521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 21621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart T* operator->() const 21721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 21821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart assert(m_ptr); 21921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return m_ptr; 22021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 22121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 22221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart T& operator*() const 22321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 22421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart assert(m_ptr); 22521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return *m_ptr; 22621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 22721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 22821e49d778a698f3e28ba2ad6b3b0430a26f9255ebartprivate: 229c710de6053e28508b4d49065f50bf10e4861b508bart void set(T* const pT, counter_t* const count_ptr) 23021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 23121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart if (m_ptr != pT) 23221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 233e32f8626804ace131a11b074784f335af71e2299bart if (m_count_ptr) 23421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 235e32f8626804ace131a11b074784f335af71e2299bart ANNOTATE_HAPPENS_BEFORE(m_count_ptr); 236e32f8626804ace131a11b074784f335af71e2299bart if (--(*m_count_ptr) == 0) 237e32f8626804ace131a11b074784f335af71e2299bart { 238e32f8626804ace131a11b074784f335af71e2299bart ANNOTATE_HAPPENS_AFTER(m_count_ptr); 239e32f8626804ace131a11b074784f335af71e2299bart delete m_ptr; 240e32f8626804ace131a11b074784f335af71e2299bart m_ptr = NULL; 241e32f8626804ace131a11b074784f335af71e2299bart delete m_count_ptr; 242e32f8626804ace131a11b074784f335af71e2299bart m_count_ptr = NULL; 243e32f8626804ace131a11b074784f335af71e2299bart } 24421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 24521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart m_ptr = pT; 24621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart m_count_ptr = count_ptr; 24721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart if (count_ptr) 248c710de6053e28508b4d49065f50bf10e4861b508bart ++(*m_count_ptr); 24921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 25021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 25121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 252c710de6053e28508b4d49065f50bf10e4861b508bart T* m_ptr; 253c710de6053e28508b4d49065f50bf10e4861b508bart counter_t* m_count_ptr; 25421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart}; 25521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 25621e49d778a698f3e28ba2ad6b3b0430a26f9255ebartclass counter 25721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart{ 25821e49d778a698f3e28ba2ad6b3b0430a26f9255ebartpublic: 25921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart counter() 26021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart : m_mutex(), m_count() 261e32f8626804ace131a11b074784f335af71e2299bart { } 262e32f8626804ace131a11b074784f335af71e2299bart ~counter() 26321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 264e32f8626804ace131a11b074784f335af71e2299bart // Data race detection tools that do not recognize the 265e32f8626804ace131a11b074784f335af71e2299bart // ANNOTATE_HAPPENS_BEFORE() / ANNOTATE_HAPPENS_AFTER() annotations in the 266e32f8626804ace131a11b074784f335af71e2299bart // smart_ptr<> implementation will report that the assignment below 267e32f8626804ace131a11b074784f335af71e2299bart // triggers a data race. 268e32f8626804ace131a11b074784f335af71e2299bart m_count = -1; 26921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 27021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart int get() const 27121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 27221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart int result; 273c710de6053e28508b4d49065f50bf10e4861b508bart m_mutex.Lock(); 27421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart result = m_count; 275c710de6053e28508b4d49065f50bf10e4861b508bart m_mutex.Unlock(); 27621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return result; 27721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 27821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart int post_increment() 27921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart { 28021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart int result; 281c710de6053e28508b4d49065f50bf10e4861b508bart m_mutex.Lock(); 28221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart result = m_count++; 283c710de6053e28508b4d49065f50bf10e4861b508bart m_mutex.Unlock(); 28421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return result; 28521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart } 28621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 28721e49d778a698f3e28ba2ad6b3b0430a26f9255ebartprivate: 288c710de6053e28508b4d49065f50bf10e4861b508bart mutable Mutex m_mutex; 289c710de6053e28508b4d49065f50bf10e4861b508bart int m_count; 29021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart}; 29121e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 29221e49d778a698f3e28ba2ad6b3b0430a26f9255ebartstatic void* thread_func(void* arg) 29321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart{ 294e32f8626804ace131a11b074784f335af71e2299bart smart_ptr<counter>* pp = reinterpret_cast<smart_ptr<counter>*>(arg); 295e32f8626804ace131a11b074784f335af71e2299bart (*pp)->post_increment(); 296e32f8626804ace131a11b074784f335af71e2299bart *pp = NULL; 297e32f8626804ace131a11b074784f335af71e2299bart delete pp; 29821e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return NULL; 29921e49d778a698f3e28ba2ad6b3b0430a26f9255ebart} 30021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 30121e49d778a698f3e28ba2ad6b3b0430a26f9255ebartint main(int argc, char** argv) 30221e49d778a698f3e28ba2ad6b3b0430a26f9255ebart{ 30321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart smart_ptr<counter> p(new counter); 304e32f8626804ace131a11b074784f335af71e2299bart const int nthreads = std::max(argc > 1 ? atoi(argv[1]) : 1, 1); 305e32f8626804ace131a11b074784f335af71e2299bart Thread T[nthreads]; 30621e49d778a698f3e28ba2ad6b3b0430a26f9255ebart 30721e49d778a698f3e28ba2ad6b3b0430a26f9255ebart p->post_increment(); 308e32f8626804ace131a11b074784f335af71e2299bart for (int i = 0; i < nthreads; ++i) 309e32f8626804ace131a11b074784f335af71e2299bart T[i].Create(thread_func, new smart_ptr<counter>(p)); 31021e49d778a698f3e28ba2ad6b3b0430a26f9255ebart p = NULL; 311e32f8626804ace131a11b074784f335af71e2299bart for (int i = 0; i < nthreads; ++i) 312e32f8626804ace131a11b074784f335af71e2299bart T[i].Join(); 31321e49d778a698f3e28ba2ad6b3b0430a26f9255ebart std::cout << "Done.\n"; 31421e49d778a698f3e28ba2ad6b3b0430a26f9255ebart return 0; 31521e49d778a698f3e28ba2ad6b3b0430a26f9255ebart} 316e32f8626804ace131a11b074784f335af71e2299bart 317e32f8626804ace131a11b074784f335af71e2299bart// Local variables: 318e32f8626804ace131a11b074784f335af71e2299bart// c-basic-offset: 2 319e32f8626804ace131a11b074784f335af71e2299bart// End: 320