[Flags]
public enum Status
{
    Success = 1<<0,     //1
    Fail = 1<<1,        //2
    Unknown = 1<<2,     //4
    isNotFail = Success | Unknown   
}

public static bool HasFlag(this int status, int flag)
{
    return (status & flag) == flag;
}

public static int SetFlag(this int flags, int flag, bool value)
{
    if (value)
        flags |= flag;
    else
        flags &= ~flag;

    return flags;
}