C++ thread synchronization example analysis

This paper analyzes the C++ thread synchronization problem, to share for your reference. Specific analysis is as follows:

This instance sets the global variable g_bContinue, sets the global variable g_bContinue in the main thread, and the worker thread detects the global variable to realize the purpose of the main thread controlling the worker thread.

The printed values of g_cnt1 and g_cnt2 are different because of the time slice switching during thread debugging.

The specific code is as follows:

//CountError. CPP: defines the entry point for the console application.
// 
#include "stdafx.h" 
#include <Windows.h> 
 
DWORD g_cnt1; 
DWORD g_cnt2; 
BOOL g_bContinue = TRUE; 
DWORD WINAPI ThreadProc(__in LPVOID lpParameter) 
{ 
  while(g_bContinue) 
  { 
    g_cnt1++; 
    g_cnt2++; 
  } 
  return 0; 
} 
 
int _tmain(int argc, _TCHAR* argv[]) 
{ 
  HANDLE hThread[2]; 
  g_cnt1 = g_cnt2 = 0; 
 
  hThread[0] = ::CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL); 
  hThread[1] = ::CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL); 
 
  Sleep(1000); 
  g_bContinue = FALSE; 
  ::WaitForMultipleObjects(2, hThread, TRUE, INFINITE); 
  printf("g_cnt1=%dn",g_cnt1); 
  printf("g_cnt2=%dn",g_cnt2); 
  ::CloseHandle(hThread[0]); 
  ::CloseHandle(hThread[1]); 
  return 0; 
}

Hope that the article described in the C++ programming to help you.