让程序只能被运行一个实例

#include <windows.h>
int main(int argc, char* argv[])
{
    HANDLE hEvent= CreateEvent(NULL,true,true,"init");
    if (hEvent)
    {
        if (GetLastError()==ERROR_ALREADY_EXISTS)
        {
            printf("Initance is running!\n");
            return 0;
        }
    }
    printf("Hello World!\n");
    Sleep(10000);
    return 0;
}