多个线程互同步问题

 

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

#define NUMTHREADS 3
#define BUFFER_SIZE 16
#define FOR_TIMES 5

HANDLE hWriteEvents[NUMTHREADS];
HANDLE hReadEvents[NUMTHREADS];
BYTE lpSharedBuffer[16]={0};

void MultiEvents(void);
VOID WriteToBuffer(VOID);

DWORD WINAPI ThreadFunction(LPVOID lpParam);

int main(){
    MultiEvents();
}

void MultiEvents(void){
    HANDLE hThread;
    DWORD i;
    for(i=0;i<NUMTHREADS;i++){
        hWriteEvents[i] = CreateEvent(NULL,FALSE,FALSE,NULL);
        if(hWriteEvents[i]==NULL){
            printf("CreateEvent failed.(%d)\n",GetLastError());
            return;
        }
        hReadEvents[i] = CreateEvent(NULL,FALSE,FALSE,NULL);
        if(hReadEvents[i]==NULL){
            printf("CreateEvent failed.(%d)\n",GetLastError());
            return;
        }
        hThread = CreateThread(NULL,0,ThreadFunction,i,0,NULL);
        if(hThread == NULL){
            printf("CreateThread failed.(%d)\n",GetLastError());
            return;
        }
    }
    WriteToBuffer();
}

VOID WriteToBuffer(VOID){
    DWORD dwWaitResult,i,j;
    for(j=0;j<FOR_TIMES;j++){
        Sleep(rand()%100);
        wsprintf(lpSharedBuffer,"shared %d",j);
        for(i=0;i<NUMTHREADS;i++){
            if(!SetEvent(hWriteEvents[i])){
                printf("SetEvent failed.(%d)\n",GetLastError());
                return;
            }
        }
        dwWaitResult = WaitForMultipleObjects(NUMTHREADS,hReadEvents,TRUE,INFINITE);
        if(dwWaitResult != WAIT_OBJECT_0){
            printf("Wait error.(%d)\n",GetLastError());
            ExitProcess(0);
        }
    }
}

DWORD WINAPI ThreadFunction(LPVOID lpParam){
    DWORD dwWaitResult;
    BYTE lpRead[16];
    DWORD j = 0;
    DWORD dwThreadIndex = (DWORD)lpParam;
    for(j=0;j<FOR_TIMES;j++){
        dwWaitResult = WaitForSingleObject(hWriteEvents[dwThreadIndex],INFINITE);
        switch (dwWaitResult){
        case WAIT_OBJECT_0:
            Sleep(rand()%10);
            CopyMemory(lpRead,lpSharedBuffer,16);
            break;
        default:
            printf("Wait error:%d\n",GetLastError());
            return 0;
        }
        printf("线程%u\t第%d次读,内容:%s\n",dwThreadIndex,j,(LPSTR)lpRead);
    }
    return 1;
}