SetEvent/ResetEvent

在自动重置事件对象中，当WaitSingleObject/WaitForMultipleObjects接收到SetEvent发送过来的信号后则返回WAIT_OBJECT_0，此时操作系统（待定）自动重置等待的事件对象（即自动将其设置为无信号状态。无论何时通过SetEvent发送过来的信号，只要未被接收到均不会被自动重置。但在未被接收之前可以调用ResetEvent手动重置等待的事件对象，此时等待的事件对象为无信号状态）。

在手动重置事件对象中，当WaitSingleObject/WaitForMultipleObjects接收到SetEvent发送过来的信号后则返回WAIT_OBJECT_0，此时需要调用ResetEvent手动重置等待的事件对象（即手动将其设置为无信号状态）。

#include <windows.h>

#include <iostream>

using namespace std;

DWORD WINAPI ThreadProc(LPVOID lpParam);

DWORD WINAPI ThreadProc2(LPVOID lpParam);

DWORD g_dwThreadID;

DWORD g_dwThreadID2;

UINT g_nTickets = 300;

HANDLE g_hEvent = NULL;

int main(int argc, char* argv[])

{

cout << "Main thread is running." << endl;

HANDLE hHandle = CreateThread(NULL, 0, ThreadProc, NULL, 0, &g_dwThreadID);

HANDLE hHandle2 = CreateThread(NULL, 0, ThreadProc2, NULL, 0, &g_dwThreadID2);

CloseHandle(hHandle);

CloseHandle(hHandle2);

g_hEvent = CreateEvent(NULL, FALSE, TRUE, NULL);

Sleep(4000);

system("pause");

return 0;

}

DWORD WINAPI ThreadProc(LPVOID lpParam)

{

// cout << "No." << g_dwThreadID << " thread is running." << endl;

while (TRUE)

{

WaitForSingleObject(g_hEvent, INFINITE);

if (g_nTickets > 0)

{

Sleep(1);

cout << "No.1-" << g_dwThreadID << " sell ticket : " << g_nTickets << endl;

g_nTickets--;

SetEvent(g_hEvent);

}

else

{

break;

}

}

return 0;

}

DWORD WINAPI ThreadProc2(LPVOID lpParam)

{

// cout << "No." << g_dwThreadID2 << " thread is running." << endl;

while (TRUE)

{

WaitForSingleObject(g_hEvent, INFINITE);

if (g_nTickets > 0)

{

Sleep(1);

cout << "No.2-" << g_dwThreadID2 << " sell ticket : " << g_nTickets << endl;

g_nTickets--;

SetEvent(g_hEvent);

}

else

{

break;

}

}

return 0;

}