#include <windows.h>
#include <iostream.h>DWORD WINAPI Fun1Proc(
LPVOID lpParameter
);DWORD WINAPI Fun2Proc(
LPVOID lpParameter
);int tickets=100;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);
Sleep(4000);
}DWORD WINAPI Fun1Proc(
LPVOID lpParameter
)
{
while(TRUE)
{
if(tickets>0)
{
Sleep(1);
cout<<"thread1 sell ticket : "<<tickets--<<endl;
}
else
break;
}
cout<<"thread1 is running"<<endl;
return 0;
}DWORD WINAPI Fun2Proc(
LPVOID lpParameter
)
{
while(TRUE)
{
if(tickets>0)
{
Sleep(1);
cout<<"thread2 sell ticket : "<<tickets--<<endl;
}
else
break;
}
cout<<"thread2 is running"<<endl;
return 0;
}
运行后会出现重复的thread1 sell ticket:32;(可能也会出现其他的数值)请问这是为什么?我知道这是不加互斥的原因,但是为什么出现重复的thread1 sell ticket:32实在不好理解,本人认为无论怎么运行,变量tickets都会自减,而且tickets是全局变量,这样运行就不太可能重复的现象,请各位高手解释一下!!!多谢!!!
#include <iostream.h>DWORD WINAPI Fun1Proc(
LPVOID lpParameter
);DWORD WINAPI Fun2Proc(
LPVOID lpParameter
);int tickets=100;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);
Sleep(4000);
}DWORD WINAPI Fun1Proc(
LPVOID lpParameter
)
{
while(TRUE)
{
if(tickets>0)
{
Sleep(1);
cout<<"thread1 sell ticket : "<<tickets--<<endl;
}
else
break;
}
cout<<"thread1 is running"<<endl;
return 0;
}DWORD WINAPI Fun2Proc(
LPVOID lpParameter
)
{
while(TRUE)
{
if(tickets>0)
{
Sleep(1);
cout<<"thread2 sell ticket : "<<tickets--<<endl;
}
else
break;
}
cout<<"thread2 is running"<<endl;
return 0;
}
运行后会出现重复的thread1 sell ticket:32;(可能也会出现其他的数值)请问这是为什么?我知道这是不加互斥的原因,但是为什么出现重复的thread1 sell ticket:32实在不好理解,本人认为无论怎么运行,变量tickets都会自减,而且tickets是全局变量,这样运行就不太可能重复的现象,请各位高手解释一下!!!多谢!!!
参考
单元模型对象必须保护共享数据
http://www.microsoft.com/china/MSDN/library/windev/COMponentdev/CDwickedtoc.mspx
Win32 Q&A
http://www.microsoft.com/msj/archive/S202B.aspx
线程Fun2Proc,线程Fun2Proc执行完后,在回来从线程Fun1Proc的保存点往下执行,然后发生了重复这是我自己的想法,望大家多多指教
WaitForSingleObject
SetEvent