Question

#include <stdio.h>
#include <process.h>
#include <wtypes.h>
typedef unsigned int (__stdcall * THREAD_FUN_TYPE)(void *);

int ThreadIp(void* param)
{
    while(true)
    {
        printf("I'm runing!\n");
    }
    return 0;
}


int main()
{
    int iThreadNum=100;
    HANDLE* phThreads = new HANDLE[iThreadNum];
    for (int i=0;i<iThreadNum;++i)
    {
        phThreads[i]=(HANDLE*)_beginthreadex(NULL, 0,  (THREAD_FUN_TYPE)ThreadIp,NULL, NULL, NULL);
    }

    int nIndex = ::WaitForMultipleObjects(iThreadNum,phThreads,1,INFINITE);
    printf("End!\n");
    return 0;
}

我希望程序在WaitForMultipleObjects停止，直到所有线程都结束（直到所有线程都成功创建）。但程序不会在WaitForMultipleObjects停止，而所有线程仍在运行。所以我尝试使用SetEvent，但仍然存在同样的问题：

int iThreadNum=100;
HANDLE* phThreads = new HANDLE[iThreadNum];
for (int i=0;i<iThreadNum;++i)
{
    phThreads[i]=CreateEvent(NULL, FALSE, FALSE,NULL);
    ResetEvent(phThreads[i]);
}
int nIndex = ::WaitForMultipleObjects(iThreadNum,phThreads,1,INFINITE);

Answer 1

您应该等待线程句柄，而不是无关事件：

尝试这样的事情：

 int iThreadNum=100;
 HANDLE* phThreads = new HANDLE[iThreadNum];
 for (int i=0;i<iThreadNum;++i)
 {
     m_iCurThreadNum=i;
     phThreads[i] = _beginthreadex(...);
  }

 int nIndex = ::WaitForMultipleObjects(iThreadNum,phThreads,1,INFINITE);

Answer 2

如果线程较少，它是否有效？ manual表示如果您的MAXIMUM_WAIT_OBJECTS超过{{1}}，则需要额外完成工作

nCount [in]指向的数组中的对象句柄数 lpHandles。对象句柄的最大数量是 MAXIMUM_WAIT_OBJECTS。此参数不能为零。

See here进行讨论。

也许值得检查等待函数返回的内容。

Answer 3

我会在调用_beginthreadex之前分配一个struct，并通过threads参数将指针传递给struct，并让struct包含一个bool，它在完成时由线程设置。

struct ThreadStruct{
    bool Done;
    char* ParamData;
    int ParamDataSize;
};

int ThreadIp(void* param)
{
    ThreadStruct* ts = (ThreadStruct*)param;
    while(true)
    {
        printf("I'm runing!\n");
    }
    ts->Done = true;
    return 0;
}

int main()
{
    int iThreadNum=100;
    HANDLE* phThreads = new HANDLE[iThreadNum];
    ThreadStruct* structs = new ThreadStruct[iThreadNum];
    for (int i=0;i<iThreadNum;++i)
    {
        ZeroMemory(structs[i], sizeof(ThreadStruct));
        phThreads[i]=(HANDLE*)_beginthreadex(NULL, 0,  (THREAD_FUN_TYPE)ThreadIp, structs[i], NULL, NULL);
        ResetEvent(phThreads[i]);
    }

    for(unsigned int i=0; i<iThreadNum;){
        if(!structs[i]->Done) i=0;
        else i++;
    }
    printf("End!\n");
    return 0;
}

C ++等待所有线程完成

3 个答案: