临界区对象问题

#include <stdio.h>
#include <windows.h>
#include <process.h>
int g_nCount1 = 0;
int g_nCount2 = 0;
BOOL g_bContinue = TRUE;
CRITICAL_SECTION g_cs; // 对存在同步问题的代码段使用临界区对象
UINT __stdcall ThreadFunc(LPVOID);
int main(int argc, char* argv[])
{
UINT uId;
HANDLE h[2];
::InitializeCriticalSection(&g_cs);// 初始化临界区对象

h[0] = (HANDLE)::_beginthreadex(NULL, 0, ThreadFunc, NULL, 0, &uId);
h[1] = (HANDLE)::_beginthreadex(NULL, 0, ThreadFunc, NULL, 0, &uId);
// 等待1 秒后通知两个计数线程结束，关闭句柄
Sleep(1000);
g_bContinue = FALSE;
::WaitForMultipleObjects(2, h, TRUE, INFINITE);
::CloseHandle(h[0]);
::CloseHandle(h[1]);// 删除临界区对象
::DeleteCriticalSection(&g_cs);
printf("g_nCount1 = %d \n", g_nCount1);
printf("g_nCount2 = %d \n", g_nCount2);
return 0;
}
UINT __stdcall ThreadFunc(LPVOID)
{ while(g_bContinue)
{ ::EnterCriticalSection(&g_cs);
g_nCount1++;
g_nCount2++;
::LeaveCriticalSection(&g_cs);
}
return 0;
}
   //我的问题：CRITICAL_SECTION g_cs; 这里只是声明一个结构体变量，::InitializeCriticalSection(&g_cs);// 初始化临界区对象，难道通过这函数就可以默认把全局变量 i 当作临界区的内容封装好，从而做到线程同步吗？从哪里看出的？是InitializeCriticalSection函数实现的？