windows下线程同步【WaitForSingleObject、WaitForMultipleObjects、CRITICAL_SECTION（用户模式）、互斥量（内核模式）、信号量（内核模式）、事件对象（内核模式）】

WaitForSingleObject函数的使用

#include <stdio.h>
#include <windows.h>
#include <process.h>

unsigned WINAPI ThreadFunc(void *arg);

int main(int argc, char *argv[])
{
    HANDLE  hThread;
    DWORD wr;
    unsigned threadID;
    int param = 5;

    hThread = (HANDLE)_beginthreadex(NULL, 0, ThreadFunc, (void *)&param, 0, &threadID);
    if((wr = WaitForSingleObject(hThread, INFINITE)) == WAIT_FAILED)
    {
        puts("thread wait error");
        return -1;
    }

    printf("wait result: %s 
", (wr == WAIT_OBJECT_0) ? "signaled" : "time-out");
    puts("end of main");
    return 0;
}

unsigned WINAPI ThreadFunc(void *arg)
{
    int i;
    int cnt = *((int *)arg);
    for(i = 0; i < cnt; i ++)
    {
        Sleep(1000);
        puts("running thread");
    }
    return 0;
}

WaitForMultipleObjects函数的使用（这个不会产生正确的结果）

#include <stdio.h>
#include <windows.h>
#include <process.h>
#define NUM_THREAD 50
unsigned WINAPI threadInc(void *arg);
unsigned WINAPI threadDec(void *arg);
long long num = 0;
int main(int argc, char *argv[])
{
    HANDLE  tHandles[NUM_THREAD];
    int i;
    printf("sizeof long long: %d 
", sizeof(long long));
    for(i = 0; i < NUM_THREAD; i ++)
    {
        if(i % 2)
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadInc, NULL, 0, NULL);
        else
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadDec, NULL, 0, NULL);
    }
    WaitForMultipleObjects(NUM_THREAD, tHandles, TRUE, INFINITE);
    printf("result: %lld 
", num);
    return 0;
}
unsigned WINAPI threadInc(void *arg)
{
    int i;
    for(i = 0; i < 50000000; i ++)
        num += 1;
    return 0;
}
unsigned WINAPI threadDec(void *arg)
{
    int i;
    for(i = 0; i < 50000000; i ++)
        num -= 1;
    return 0;
}

CRITICAL_SECTION的使用

#include <stdio.h>
#include <windows.h>
#include <process.h>
#define NUM_THREAD 50
unsigned WINAPI threadInc(void *arg);
unsigned WINAPI threadDec(void *arg);
long long num = 0;
CRITICAL_SECTION cs;
int main(int argc, char *argv[])
{
    HANDLE  tHandles[NUM_THREAD];
    int i;
    InitializeCriticalSection(&cs);
    for(i = 0; i < NUM_THREAD; i ++)
    {
        if(i % 2)
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadInc, NULL, 0, NULL);
        else
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadDec, NULL, 0, NULL);
    }
    WaitForMultipleObjects(NUM_THREAD, tHandles, TRUE, INFINITE);
    DeleteCriticalSection(&cs);
    printf("result: %lld 
", num);
    return 0;
}
unsigned WINAPI threadInc(void *arg)
{
    int i;
    EnterCriticalSection(&cs);
    for(i = 0; i < 50000000; i ++)
        num += 1;
    LeaveCriticalSection(&cs);
    return 0;
}
unsigned WINAPI threadDec(void *arg)
{
    int i;
    EnterCriticalSection(&cs);
    for(i = 0; i < 50000000; i ++)
        num -= 1;
    LeaveCriticalSection(&cs);
    return 0;
}

基于互斥量的同步

#include <stdio.h>
#include <windows.h>
#include <process.h>

#define NUM_THREAD 50
unsigned WINAPI threadInc(void *arg);
unsigned WINAPI threadDec(void *arg);

long long num = 0;
HANDLE hMutex;

int main(int argc, char *argv[])
{
    HANDLE  tHandles[NUM_THREAD];
    int i;

    hMutex = CreateMutex(NULL, FALSE, NULL);
    for(i = 0; i < NUM_THREAD; i ++)
    {
        if(i % 2)
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadInc, NULL, 0, NULL);
        else
            tHandles[i] = (HANDLE)_beginthreadex(NULL, 0, threadDec, NULL, 0, NULL);
    }

    WaitForMultipleObjects(NUM_THREAD, tHandles, TRUE, INFINITE);
    CloseHandle(hMutex);
    printf("result: %lld 
", num);
    return 0;
}

unsigned WINAPI threadInc(void *arg)
{
    int i;
    WaitForSingleObject(hMutex, INFINITE);
    for(i = 0; i < 50000000; i ++)
        num += 1;
    ReleaseMutex(hMutex);
    return 0;
}

unsigned WINAPI threadDec(void *arg)
{
    int i;
    WaitForSingleObject(hMutex, INFINITE);
    for(i = 0; i < 50000000; i ++)
        num -= 1;
    ReleaseMutex(hMutex);
    return 0;
}

基于信号量的同步

#include <stdio.h>
#include <windows.h>
#include <process.h>

unsigned WINAPI Read(void *arg);
unsigned WINAPI Accu(void *arg);

static HANDLE semOne;
static HANDLE semTwo;
static int num;

int main(int argc, char *argv[])
{
    HANDLE  hThread1, hThread2;
    semOne = CreateSemaphore(NULL, 0, 1, NULL);
    semTwo = CreateSemaphore(NULL, 1, 1, NULL);

    hThread1 = (HANDLE)_beginthreadex(NULL, 0, Read, NULL, 0, NULL);
    hThread2 = (HANDLE)_beginthreadex(NULL, 0, Accu, NULL, 0, NULL);

    WaitForSingleObject(hThread1, INFINITE);
    WaitForSingleObject(hThread2, INFINITE);

    CloseHandle(semOne);
    CloseHandle(semTwo);
    return 0;
}

unsigned WINAPI Read(void *arg)
{
    int i;
    for(i = 0; i < 5; i ++)
    {
        fputs("Input num: ", stdout);
        WaitForSingleObject(semTwo, INFINITE);
        scanf("%d", &num);
        ReleaseSemaphore(semOne, 1, NULL);
    }
    return 0;
}

unsigned WINAPI Accu(void *arg)
{
    int sum = 0, i;
    for(i = 0; i < 5; i ++)
    {
        WaitForSingleObject(semOne, INFINITE);
        sum += num;
        ReleaseSemaphore(semTwo, 1, NULL);
    }
    printf("Result: %d 
", sum);
    return 0;
}

基于事件对象的同步

#include <stdio.h>
#include <windows.h>
#include <process.h>
#define STR_LEN 100

unsigned WINAPI NumberOfA(void *arg);
unsigned WINAPI NumberOfOthers(void *arg);

static char str[STR_LEN];
static HANDLE hEvent;

int main(int argc, char *argv[])
{
    HANDLE  hThread1, hThread2;
    hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    hThread1 = (HANDLE)_beginthreadex(NULL, 0, NumberOfA, NULL, 0, NULL);
    hThread2 = (HANDLE)_beginthreadex(NULL, 0, NumberOfOthers, NULL, 0, NULL);

    fputs("Input string: ", stdout);
    fgets(str, STR_LEN, stdin);
    SetEvent(hEvent);

    WaitForSingleObject(hThread1, INFINITE);
    WaitForSingleObject(hThread2, INFINITE);
    ResetEvent(hEvent);
    CloseHandle(hEvent);
    return 0;
}

unsigned WINAPI NumberOfA(void *arg)
{
    int i, cnt = 0;
    WaitForSingleObject(hEvent, INFINITE);
    for(i = 0; str[i] != 0; i ++)
    {
        if(str[i] == 'A')
            cnt ++;
    }
    printf("num of A: %d 
", cnt);
    return 0;
}

unsigned WINAPI NumberOfOthers(void *arg)
{
    int i, cnt = 0;
    WaitForSingleObject(hEvent, INFINITE);
    for(i = 0; str[i] != 0; i ++)
    {
        if(str[i] != 'A')
            cnt ++;
    }
    printf("Number of others: %d 
", cnt - 1);
    return 0;
}