WaitForMultipleObjects 是我以 pthread 移植 MFC 架構 至 Android 的一環; 因為覺得還蠻實用的, 也因為蠻簡單的, 所以放到部落格上供讀者參考. 有錯誤之處, 請讀者不吝指出. 但切記, 在應用時一定要先測試其效能. Android NDK 裡面的 pthread 並不支援 pthread_testcancel(),pthread_cancel().. , 因此下文內的 THREAD_CANCEL 並沒有用上, 只是我縱情想像力寫的.
Global 函數
所需要的靜態函數有 2 . 我解釋一下 TimespecAdd() ; 它需傳入兩個 timespec 結構, 然後將此 2 個 timespec 結構相加計算, 然後傳出此相加之後的 timespec 結構. timespec 結構是用來表示高精確度時間的 C 結構; 至於真正的精確度為何? 則與 kernel, platform 有關.
void CleanupLock(void *param) {
pthread_mutex_unlock((pthread_mutex_t *)param);
}
void TimespecAdd(const struct timespec* a, const struct timespec* b, struct timespec* out) {
time_t sec = a->tv_sec + b->tv_sec;
long nsec = a->tv_nsec + b->tv_nsec;
sec += nsec / 1000000000L;
nsec = nsec % 1000000000L;
out->tv_sec = sec;
out->tv_nsec = nsec;
}
Event.h
API 是這樣的:
HANDLE CreateEvent(void *pAttr, int bManualReset, int bInitialState, const char *szName);
int CloseEvent(HANDLE hObject);
int SetEvent(HANDLE hEvent);
int ResetEvent(HANDLE hEvent);
int PulseEvent(HANDLE hEvent);
unsigned int WaitForSingleObject(HANDLE hEvent, unsigned int dwMilliseconds);
unsigned int WaitForMultipleObjects(unsigned int nCount, const HANDLE *lpHandles, int bWaitAll, unsigned int dwMilliseconds);
#if !defined(AFX_EVENT_H__285CFF59_8261_4DE7_84F3_43E209FEF60C__INCLUDED_)
#define AFX_EVENT_H__285CFF59_8261_4DE7_84F3_43E209FEF60C__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#ifndef INFINITE
#define INFINITE 0xFFFFFFFF
#endif
#ifdef ETIMEDOUT
#define WAIT_TIMEOUT ETIMEDOUT
#else
#define WAIT_TIMEOUT 0x00000102L
#endif
#define WAIT_FAILED 0xFFFFFFFFL
#define WAIT_OBJECT_0 0x00000000L
#define WAIT_ABANDONED 0x00000080L
#define WAIT_FOR_ANY_ONE_EVENTS 0
#define WAIT_FOR_ALL_EVENTS 1
#define MANUAL_RESET 1
#define AUTO_RESET 0
#define SET 1
#define RESET 0
//////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////
struct event_t {
int id;
int type;
char name[256];
int manual_reset;
pthread_cond_t event;
};
//////////////////////////////////////////////////////////////////////
// extern
//////////////////////////////////////////////////////////////////////
#if defined(__cplusplus) || defined(__CPLUSPLUS__)
extern "C" {
#endif
HANDLE CreateEvent(void *pAttr, int bManualReset, int bInitialState, const char *szName);
int CloseEvent(HANDLE hObject);
int SetEvent(HANDLE hEvent);
int ResetEvent(HANDLE hEvent);
int PulseEvent(HANDLE hEvent);
unsigned int WaitForSingleObject(HANDLE hEvent, unsigned int dwMilliseconds);
unsigned int WaitForMultipleObjects(unsigned int nCount, const HANDLE *lpHandles, int bWaitAll, unsigned int dwMilliseconds);
#if defined(__cplusplus) || defined(__CPLUSPLUS__)
}
#endif
#endif // !defined(AFX_EVENT_H__285CFF59_8261_4DE7_84F3_43E209FEF60C__INCLUDED_)
// StdAfx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#if !defined(AFX_STDAFX_H__3F41C39C_B21A_4F9F_BD57_0061B53E9B86__INCLUDED_)
#define AFX_STDAFX_H__3F41C39C_B21A_4F9F_BD57_0061B53E9B86__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#ifdef WIN32
#define VC_EXTRALEAN // Exclude rarely-used stuff from Windows headers
#include <afxwin.h> // MFC core and standard components
#include <afxext.h> // MFC extensions
#include <afxdtctl.h> // MFC support for Internet Explorer 4 Common Controls
#ifndef _AFX_NO_AFXCMN_SUPPORT
#include <afxcmn.h> // MFC support for Windows Common Controls
#endif // _AFX_NO_AFXCMN_SUPPORT
#endif // WIN32
//{{AFX_INSERT_LOCATION}}
#ifndef NULL
#define NULL 0
#endif
#ifndef BOOL
#define BOOL int
#endif
#ifndef INT
#define INT int
#endif
#ifndef UINT
#define UINT unsigned int
#endif
#ifndef DWORD
#define DWORD unsigned long
#endif
#ifndef LONG
#define LONG long
#endif
#ifndef WORD
#define WORD unsigned short
#endif
#ifndef BYTE
#define BYTE unsigned char
#endif
#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif
#ifndef WPARAM
#define WPARAM unsigned int
#endif
#ifndef LPARAM
#define LPARAM unsigned int
#endif
#ifndef LRESULT
#define LRESULT unsigned int
#endif
#ifndef INFINITE
#define INFINITE 0XFFFFFFFF // Infinite timeout
#endif
#ifndef SIGNED
#define SIGNED int
#endif
#ifndef UCHAR
#define UCHAR unsigned char
#endif
#ifndef LONG
#define LONG int
#endif
#ifndef INT64
#define INT64 signed long long
#endif
#ifndef UINT64
#define UINT64 unsigned long long
#endif
#ifndef FLOAT
#define FLOAT float
#endif
typedef void *HANDLE;
typedef unsigned char U8_T;
typedef unsigned char U8_B_T;
typedef unsigned char U8_S_T;
typedef unsigned short U16_T;
typedef unsigned long U32_T;
typedef unsigned long U32_IP_T;
typedef char I8_T;
typedef short I16_T;
typedef long I32_T;
#define ULONGLONGINT unsigned long long int
#define BIT0 (1<<0)
#define BIT1 (1<<1)
#define BIT2 (1<<2)
#define BIT3 (1<<3)
#define BIT4 (1<<4)
#define BIT5 (1<<5)
#define BIT6 (1<<6)
#define BIT7 (1<<7)
#endif // !defined(AFX_STDAFX_H__3F41C39C_B21A_4F9F_BD57_0061B53E9B86__INCLUDED_)
Global 變數
struct event_t {
int id;
int type;
char name[256];
int manual_reset;
pthread_cond_t event;
};
static HANDLE pso[] = {
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};
static unsigned long long int cs = 0;
static pthread_mutex_t cm = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t si = PTHREAD_MUTEX_INITIALIZER;
cm 是一個 mutex . pso 是 Events 陣列 , 陣列中每一個元素可能指向一個 event_t 結構, 而這結構則包含了一個 pthresd 條件變數 pthread_cond_t event . cs 後面會提到. event_t 結構裡有一成員 manual_reset, 1 的時候是手動 reset, 0 的時候是自動 reset .
CreateEvent / CloseEvent
CreateEvents() 用來產生一個 Event 物件; 而 CloseEvent() 則用來刪除這個物件. si 這個 mutex 則做為執行緒間 cteate/close 之間的互斥機制. CreateEvents() 有幾個重要的參數:
1. bManualReset: 設為1 是手動 reset ; 設為 0 是自動 reset .
2. bInitialState: bInitialState 是指這個要產生的 Event 物件它的初始狀態是 set 或是 reset . 這狀態如果是 reset, 則執行緒呼叫 WaitFor.... 等函數會被 block; 如果是 set, 則會 unblock . Event 物件的狀態是儲存在全域變數 cs 的其中 1個 bit.
HANDLE CreateEvent(void *pAttr, int bManualReset, int bInitialState, const char *szName) {
int i;
struct event_t *p = 0;
unsigned long long int mask = 0;
#ifdef THREAD_CANCEL
int last_type;
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif // THREAD_CANCEL
pthread_mutex_lock(&si);
pthread_cleanup_push(CleanupLock, (void *)&si);
for (i = 0; i < sizeof(unsigned long long int); i++) {
if (pso[i] == 0) {
pso[i] = malloc(sizeof(struct event_t));
p = (struct event_t *)pso[i], assert(p);
memset(p, 0, sizeof(struct event_t));
p->id = i;
mask = 1 << i;
break;
}
}
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif // THREAD_CANCEL
if(p == 0) return 0;
strcpy(p->name, szName);
p->type = 1;
p->manual_reset = bManualReset;
pthread_cond_init(&p->event, NULL);
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
if (bInitialState) cs |= mask;
else cs &= ~mask;
pthread_cleanup_pop(1);
return (void *)p;
}
int CloseEvent(HANDLE hObject) {
struct event_t *p;
unsigned long long int mask;
int i;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hObject == 0) return 0;
p = (struct event_t *)hObject;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&si);
pthread_cleanup_push(CleanupLock, (void *)&si);
pso[i] = 0;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
free(hObject);
return 0;
}
SetEvent / ResetEvent / PulseEvent
SetEvent() / ResetEvent() 是用來 set 或是 reset 產生的 Event 物件它內部的狀態. 這 Event 物件的狀態是儲存在全域變數 cs 的其中 1個 bit. 我們用 cm 這個 mutex 則做為執行緒間所有 Events set/reset 之間的互斥機制. 這邊要提到 SetEvent() 與 PulseEvent() 有什麼不同呢? 假設執行緒 T1, T2 阻斷 (block, 是動詞) 在 E 這個 Event 物件, 如果 E 是 自動 reset 的話, SetEvent() 只能 unblock T1 或是 T2, 而 PulseEvent() 則能同時 unblock T1 以及 T2.
int SetEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
int res;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs |= mask;
res = pthread_cond_signal(&p->event);
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return (res == 0) ? 1 : 0;
}
int ResetEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return 1;
}
int PulseEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
int res;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs |= mask;
res = pthread_cond_broadcast(&p->event);
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return (res == 0) ? 1 : 0;
}
WaitForMultipleObjects
直接來看重點吧 (WaitForMultipleObjects) . 關於 Events 我使用一個 64位元的變數 cs 來代表它們的 set / reset, set為1 reset為0 . 也就是說 WaitForMultiples 最多只能 wait 64 個 Events 物件. 一般來說, 這是夠用了. WaitForMultipleObjects() 參數1 傳入 Events 數目; 參數2 傳入我們關注的 Events 陣列; 參數3 傳入是否為 WaitAll; 參數4 則傳入 TimeOut 的 mini-seconds . 這與 MSDN 上的 prototpye 一致, https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms687025(v=vs.85).aspx .
WaitForMultipleObjects 作用是 Wait for the thread to signal one of the event objects . 返回值則是 WAIT_TIMEOUT, WAIT_FAIL, 以及 WAIT_OBJECT_0, +1 +2 ....
unsigned int WaitForMultipleObjects(unsigned int nCount, const HANDLE *lpHandles, int bWaitAll, unsigned int dwMilliseconds) {
unsigned int r;
int i;
int res = EINVAL;
HANDLE handle = 0;
struct event_t *p;
unsigned long long int mask = 0;
struct timespec ts;
struct timespec dt = { 0 }, at = { 0 };
unsigned long long int id = 0;
#ifdef THREAD_CANCEL
int last_type;
#endif
assert(nCount > 0), assert(nCount <= sizeof(unsigned long long int)), assert(lpHandles != 0);
clock_gettime(CLOCK_REALTIME, &ts);
if(dwMilliseconds != INFINITE) {
memset(&dt, 0, sizeof(dt));
dt.tv_sec = dwMilliseconds / 1000;
dt.tv_nsec = (dwMilliseconds % 1000) * 1000000;
TimespecAdd(&ts, &dt, &at);
}
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
mask = 0;
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
mask |= (1 << p->id);
}
///////////////////////////////////////////////////////////
// wait for any one of the events
if (!bWaitAll) {
#if 0
while (!(mask & cs)) {
#else
if (!(mask & cs)) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if(res == 0) break;
if(res == ETIMEDOUT) {
r = WAIT_TIMEOUT;
goto EXIT;
}
if(res == EINVAL) {
r = WAIT_FAILED;
goto EXIT;
}
}
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
id = p->id;
if (cs & (1 << id)) {
if(!p->manual_reset) cs &= ~(1 << id);
break;
}
}
r = WAIT_OBJECT_0 + (unsigned int)i;
goto EXIT;
}
///////////////////////////////////////////////////////////
// wait for all of the events
#if 0
while ((mask & cs) != cs) {
#else
if ((mask & cs) != cs) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if(res == 0) break;
if(res == ETIMEDOUT) {
r = WAIT_TIMEOUT;
goto EXIT;
}
if(res == EINVAL) {
r = WAIT_FAILED;
goto EXIT;
}
}
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
id = p->id;
if (cs & (1 << id)) {
if(!p->manual_reset) cs &= ~(1 << id);
}
}
r = WAIT_OBJECT_0;
goto EXIT;
///////////////////////////////////////////////////////////
// returns
EXIT:
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return r;
}
文件中的 mutural exclution 機制, 我使用的 clean-up stack. pthread_cleanup_push() / pthread_cleanup_pop() 互為 counter-part 函式. 由於 pthread_cleanup_push() / pthread_cleanup_pop() 實做上是 macro 因此文件上我用了 goto .
先來看 wait for any one of the events ; 通常我們會用 wait for any one of the events. 觀察的重點是 cs 這個 64位元的全域變數 (靜態變數, 因只有 Event.cpp 這個模組使用) . 通常執行緒 T 會 block 在 pthread_cond_wait() 或 pthread_cond_timedwait, 如果 WaitForMultipleObjects() 最後一個參數是 INFINITE, 則執行緒會 block 在 pthread_cond_wait(), 否則執行緒會 block 在 pthread_cond_timedwait() . 這最後一個參數的單位是 mini-seconds. 當有其他執行緒呼叫 SetEvent() 後, SetEvent() 會準確地 set cs 這個 64位元的全域變數造成執行緒 T 自 pthread_cond_wait() 返回. 之後我們計算 unblock 自那一個 Event 物件, 告知執行緒 T. WAIT_OBJECT_0 就是我們關注的 Events 中的第1個, (WAIT_OBJECT_0+1) 就是我們關注的 Events 中的第2個, ...
wait for all of the events 就請讀者自行參閱. 要注意的一點是: 如果要 wait for all of the events , 這些關注的 events 都要 manual reset. 原因是如果不全是 manual reset 的話, 執行緒 T 會 block forever.
unsigned int WaitForSingleObject(HANDLE hEvent, unsigned int dwMilliseconds) {
struct event_t *p;
unsigned long long int mask;
int i;
int res = EINVAL;
struct timespec ts;
struct timespec dt = { 0 }, at = { 0 };
#ifdef THREAD_CANCEL
int last_type;
#endif // THREAD_CANCEL
if(hEvent == 0) return WAIT_FAILED;
p = (struct event_t *)hEvent;
i = p->id;
mask = (1 << i);
if (dwMilliseconds != INFINITE) {
clock_gettime(CLOCK_REALTIME, &ts);
memset(&dt, 0, sizeof(dt));
dt.tv_sec += (dwMilliseconds / 1000);
dt.tv_nsec += ((dwMilliseconds % 1000) * 1000000);
TimespecAdd(&ts, &dt, &at);
}
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif // THREAD_CANCEL
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
#if 0
while((cs & mask) != mask) {
#else
if((cs & mask) != mask) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if (res != 0) break;
}
// auto reset
if(!p->manual_reset) cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif // THREAD_CANCEL
if (res == 0) return WAIT_OBJECT_0;
else if (res == ETIMEDOUT) return WAIT_TIMEOUT;
else return WAIT_FAILED;
}
還有一個函數 WaitForSingleObject(), 我把它列出來. 細節我就不多做說明了.
Event.cpp
#include "StdAfx.h"
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <strings.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <dirent.h>
#include <sys/mount.h>
#include <pthread.h>
#include <android/log.h>
//#include <sys/uio.h>
//#include "Misc.h"
#include "Event.h"
//////////////////////////////////////////////////////////////////////
// static
//////////////////////////////////////////////////////////////////////
static pthread_mutex_t si = PTHREAD_MUTEX_INITIALIZER;
static HANDLE pso[] = {
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};
static unsigned long long int cs = 0;
static pthread_mutex_t cm = PTHREAD_MUTEX_INITIALIZER;
//////////////////////////////////////////////////////////////////////
// routines
//////////////////////////////////////////////////////////////////////
HANDLE CreateEvent(void *pAttr, int bManualReset, int bInitialState, const char *szName) {
int i;
struct event_t *p = 0;
unsigned long long int mask = 0;
#ifdef THREAD_CANCEL
int last_type;
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif // THREAD_CANCEL
pthread_mutex_lock(&si);
pthread_cleanup_push(CleanupLock, (void *)&si);
for (i = 0; i < sizeof(unsigned long long int); i++) {
if (pso[i] == 0) {
pso[i] = malloc(sizeof(struct event_t));
p = (struct event_t *)pso[i], assert(p);
memset(p, 0, sizeof(struct event_t));
p->id = i;
mask = 1 << i;
break;
}
}
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif // THREAD_CANCEL
if(p == 0) return 0;
strcpy(p->name, szName);
p->type = 1;
p->manual_reset = bManualReset;
pthread_cond_init(&p->event, NULL);
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
if (bInitialState) cs |= mask;
else cs &= ~mask;
pthread_cleanup_pop(1);
return (void *)p;
}
int CloseEvent(HANDLE hObject) {
struct event_t *p;
unsigned long long int mask;
int i;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hObject == 0) return 0;
p = (struct event_t *)hObject;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&si);
pthread_cleanup_push(CleanupLock, (void *)&si);
pso[i] = 0;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
free(hObject);
return 0;
}
int SetEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
int res;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs |= mask;
res = pthread_cond_signal(&p->event);
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return (res == 0) ? 1 : 0;
}
int ResetEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return 1;
}
int PulseEvent(HANDLE hEvent) {
struct event_t *p;
unsigned long long int mask;
int i;
int res;
#ifdef THREAD_CANCEL
int last_type;
#endif
if(hEvent == 0) return 0;
p = (struct event_t *)hEvent;
i = p->id;
mask = 1 << i;
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
cs |= mask;
res = pthread_cond_broadcast(&p->event);
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return (res == 0) ? 1 : 0;
}
unsigned int WaitForSingleObject(HANDLE hEvent, unsigned int dwMilliseconds) {
struct event_t *p;
unsigned long long int mask;
int i;
int res = EINVAL;
struct timespec ts;
struct timespec dt = { 0 }, at = { 0 };
#ifdef THREAD_CANCEL
int last_type;
#endif // THREAD_CANCEL
if(hEvent == 0) return WAIT_FAILED;
p = (struct event_t *)hEvent;
i = p->id;
mask = (1 << i);
if (dwMilliseconds != INFINITE) {
clock_gettime(CLOCK_REALTIME, &ts);
memset(&dt, 0, sizeof(dt));
dt.tv_sec += (dwMilliseconds / 1000);
dt.tv_nsec += ((dwMilliseconds % 1000) * 1000000);
TimespecAdd(&ts, &dt, &at);
}
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif // THREAD_CANCEL
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
#if 0
while((cs & mask) != mask) {
#else
if((cs & mask) != mask) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if (res != 0) break;
}
// auto reset
if(!p->manual_reset) cs &= ~mask;
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif // THREAD_CANCEL
if (res == 0) return WAIT_OBJECT_0;
else if (res == ETIMEDOUT) return WAIT_TIMEOUT;
else return WAIT_FAILED;
}
unsigned int WaitForMultipleObjects(unsigned int nCount, const HANDLE *lpHandles, int bWaitAll, unsigned int dwMilliseconds) {
unsigned int r;
int i;
int res = EINVAL;
HANDLE handle = 0;
struct event_t *p;
unsigned long long int mask = 0;
struct timespec ts;
struct timespec dt = { 0 }, at = { 0 };
unsigned long long int id = 0;
#ifdef THREAD_CANCEL
int last_type;
#endif
assert(nCount > 0), assert(nCount <= sizeof(unsigned long long int)), assert(lpHandles != 0);
clock_gettime(CLOCK_REALTIME, &ts);
if(dwMilliseconds != INFINITE) {
memset(&dt, 0, sizeof(dt));
dt.tv_sec = dwMilliseconds / 1000;
dt.tv_nsec = (dwMilliseconds % 1000) * 1000000;
TimespecAdd(&ts, &dt, &at);
}
#ifdef THREAD_CANCEL
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &last_type);
#endif
pthread_mutex_lock(&cm);
pthread_cleanup_push(CleanupLock, (void *)&cm);
mask = 0;
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
mask |= (1 << p->id);
}
///////////////////////////////////////////////////////////
// wait for any one of the events
if (!bWaitAll) {
#if 0
while (!(mask & cs)) {
#else
if (!(mask & cs)) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if(res == 0) break;
if(res == ETIMEDOUT) {
r = WAIT_TIMEOUT;
goto EXIT;
}
if(res == EINVAL) {
r = WAIT_FAILED;
goto EXIT;
}
}
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
id = p->id;
if (cs & (1 << id)) {
if(!p->manual_reset) cs &= ~(1 << id);
break;
}
}
r = WAIT_OBJECT_0 + (unsigned int)i;
goto EXIT;
}
///////////////////////////////////////////////////////////
// wait for all of the events
#if 0
while ((mask & cs) != cs) {
#else
if ((mask & cs) != cs) {
#endif
if (dwMilliseconds == INFINITE) res = pthread_cond_wait(&p->event, &cm);
else res = pthread_cond_timedwait(&p->event, &cm, &at);
if(res == 0) break;
if(res == ETIMEDOUT) {
r = WAIT_TIMEOUT;
goto EXIT;
}
if(res == EINVAL) {
r = WAIT_FAILED;
goto EXIT;
}
}
for (i = 0; i < (int)nCount; i++) {
handle = lpHandles[i];
p = (struct event_t *)handle;
id = p->id;
if (cs & (1 << id)) {
if(!p->manual_reset) cs &= ~(1 << id);
}
}
r = WAIT_OBJECT_0;
goto EXIT;
///////////////////////////////////////////////////////////
// returns
EXIT:
pthread_cleanup_pop(1);
#ifdef THREAD_CANCEL
pthread_testcancel();
pthread_setcanceltype(last_type, NULL);
#endif
return r;
}
Example
Example 我先使用 MSDN 裡面的範例,
https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms687055(v=vs.85).aspx.
有空的話我再修改這一段.
#include <windows.h>
#include <stdio.h>
HANDLE ghEvents[2];
DWORD WINAPI ThreadProc( LPVOID );
int main( void ) {
HANDLE hThread;
DWORD i, dwEvent, dwThreadID;
// Create two event objects
for (i = 0; i < 2; i++) {
ghEvents[i] = CreateEvent(
NULL, // default security attributes
FALSE, // auto-reset event object
FALSE, // initial state is nonsignaled
NULL); // unnamed object
if (ghEvents[i] == NULL) {
printf("CreateEvent error: %d\n", GetLastError() );
ExitProcess(0);
}
}
// Create a thread
hThread = CreateThread(
NULL, // default security attributes
0, // default stack size
(LPTHREAD_START_ROUTINE) ThreadProc,
NULL, // no thread function arguments
0, // default creation flags
&dwThreadID); // receive thread identifier
if( hThread == NULL ) {
printf("CreateThread error: %d\n", GetLastError());
return 1;
}
// Wait for the thread to signal one of the event objects
dwEvent = WaitForMultipleObjects(
2, // number of objects in array
ghEvents, // array of objects
FALSE, // wait for any object
5000); // five-second wait
// The return value indicates which event is signaled
switch (dwEvent) {
// ghEvents[0] was signaled
case WAIT_OBJECT_0 + 0:
// TODO: Perform tasks required by this event
printf("First event was signaled.\n");
break;
// ghEvents[1] was signaled
case WAIT_OBJECT_0 + 1:
// TODO: Perform tasks required by this event
printf("Second event was signaled.\n");
break;
case WAIT_TIMEOUT:
printf("Wait timed out.\n");
break;
// Return value is invalid.
default:
printf("Wait error: %d\n", GetLastError());
ExitProcess(0);
}
// Close event handles
for (i = 0; i < 2; i++)
CloseHandle(ghEvents[i]);
return 0;
}
DWORD WINAPI ThreadProc( LPVOID lpParam ) {
// lpParam not used in this example
UNREFERENCED_PARAMETER( lpParam);
// Set one event to the signaled state
if ( !SetEvent(ghEvents[0]) ) {
printf("SetEvent failed (%d)\n", GetLastError());
return 1;
}
return 0;
}
Email: jasonc@mail2000.com.tw . 請尊重原創, 使用圖文時載明出處. 謝謝.
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不錯, 可讀性很高.
清楚明瞭，很棒.