最近在学习VC的多线程,孙鑫老师VC视频中的多线程同步,用CriticalSection方法时,有时候运行时正常,有时候windows会报错说遇到问题。
并且程序正确和错误出现时情况是随机的。我的CPU是超线程的,在同学的酷睿CPU上页遇到一样的情况。
以下代码是孙鑫老师VC视频中的,【win32 console application的程序】大家看看到底是什么问题。
#include <windows.h>
#include <iostream.h>DWORD WINAPI Fun1Proc(
LPVOID lpParameter // thread data
);DWORD WINAPI Fun2Proc(
LPVOID lpParameter // thread data
);int tickets=100;CRITICAL_SECTION g_csA;void main()
{
HANDLE hThread1;
HANDLE hThread2;
hThread1=CreateThread(NULL,0,Fun1Proc,NULL,0,NULL);
hThread2=CreateThread(NULL,0,Fun2Proc,NULL,0,NULL);
CloseHandle(hThread1);
CloseHandle(hThread2); InitializeCriticalSection(&g_csA);
Sleep(4000); DeleteCriticalSection(&g_csA);
}DWORD WINAPI Fun1Proc(
LPVOID lpParameter // thread data
)
{
while(TRUE)
{
EnterCriticalSection(&g_csA); if(tickets>0)
{
Sleep(1);
cout<<"thread1 sell ticket : "<<tickets--<<endl;
}
else
break;
LeaveCriticalSection(&g_csA);
}
return 0;
}DWORD WINAPI Fun2Proc(
LPVOID lpParameter // thread data
)
{
while(TRUE)
{
EnterCriticalSection(&g_csA);
if(tickets>0)
{
Sleep(1);
cout<<"thread2 sell ticket : "<<tickets--<<endl;
}
else
break;
LeaveCriticalSection(&g_csA);
}
cout<<"thread2 is running!"<<endl;
return 0;
}
并且程序正确和错误出现时情况是随机的。我的CPU是超线程的,在同学的酷睿CPU上页遇到一样的情况。
以下代码是孙鑫老师VC视频中的,【win32 console application的程序】大家看看到底是什么问题。
#include <windows.h>
#include <iostream.h>DWORD WINAPI Fun1Proc(
LPVOID lpParameter // thread data
);DWORD WINAPI Fun2Proc(
LPVOID lpParameter // thread data
);int tickets=100;CRITICAL_SECTION g_csA;void main()
{
HANDLE hThread1;
HANDLE hThread2;
hThread1=CreateThread(NULL,0,Fun1Proc,NULL,0,NULL);
hThread2=CreateThread(NULL,0,Fun2Proc,NULL,0,NULL);
CloseHandle(hThread1);
CloseHandle(hThread2); InitializeCriticalSection(&g_csA);
Sleep(4000); DeleteCriticalSection(&g_csA);
}DWORD WINAPI Fun1Proc(
LPVOID lpParameter // thread data
)
{
while(TRUE)
{
EnterCriticalSection(&g_csA); if(tickets>0)
{
Sleep(1);
cout<<"thread1 sell ticket : "<<tickets--<<endl;
}
else
break;
LeaveCriticalSection(&g_csA);
}
return 0;
}DWORD WINAPI Fun2Proc(
LPVOID lpParameter // thread data
)
{
while(TRUE)
{
EnterCriticalSection(&g_csA);
if(tickets>0)
{
Sleep(1);
cout<<"thread2 sell ticket : "<<tickets--<<endl;
}
else
break;
LeaveCriticalSection(&g_csA);
}
cout<<"thread2 is running!"<<endl;
return 0;
}
else
break;
LeaveCriticalSection(&g_csA);即换后为这个样子else
{
LeaveCriticalSection(&g_csA);
break;
}
LeaveCriticalSection(&g_csA);
如Waitfor,Release打头的函数,其自身的运行也是不能保证不被中断,所以还是要从程序的设计上想办法,对共享变量,特别是象对象这种很大的共享变量,要慎重。即使单核的机器也避免不了这个问题。