C++ - 以 2 种不同的方式运行相同的 mktime（） 逻辑，产生意外结果

问：

我正在使用 strptime（） 和 mktime 将字符串中的时间转换为长时间。奇怪的是，以两种不同的方式使用相同的代码会产生不同的结果。不过，在这两种情况下，struct tm 的值是相同的。

请告诉我我做错了什么。

类型 1

int main()
{
    string time = "2023-03-02 00:00:00";
    struct tm tm;
    strptime(time.c_str(), "%Y-%d-%m %H:%M:%S", &tm);   //it is supposed to give you value decreased by 1900 so if it gives you 113 it means the year is 2013. Month will also be decreased by 1, i.e. if it gives you 1, it is actually February. Just add these values:
    //mktime expects the value given by strptime itslf. No need to do any modifications.
    time_t t = mktime(&tm);
    cout<<"tm_sec: "<<tm.tm_sec<<endl;
    cout<<"tm_min: "<<tm.tm_min<<endl;
    cout<<"tm_hour: "<<tm.tm_hour<<endl;
    cout<<"tm_mday: "<<tm.tm_mday<<endl;
    cout<<"tm_mon: "<<tm.tm_mon<<endl;
    cout<<"tm_year: "<<tm.tm_year<<endl;    
    cout<<"tm_wday: "<<tm.tm_wday<<endl;
    cout<<"tm_yday: "<<tm.tm_yday<<endl;
    cout<<"tm_isdst: "<<tm.tm_isdst<<endl;
    cout<<t<<endl;
    return 0;
}

这将按预期运行 （t=1675382400）

类型 2

time_t convert_datetime_string_to_long_time(string time)
    {
        //convert string time to long unix time
        struct tm tm;
        strptime(time.c_str(), "%Y-%d-%m %H:%M:%S", &tm);   //it is supposed to give you value decreased by 1900 so if it gives you 113 it means the year is 2013. Month will also be decreased by 1, i.e. if it gives you 1, it is actually February. Just add these values:
        //mktime expects the value given by strptime itslf. No need to do any modifications.
        
        cout<<"tm_sec: "<<tm.tm_sec<<endl;
        cout<<"tm_min: "<<tm.tm_min<<endl;
        cout<<"tm_hour: "<<tm.tm_hour<<endl;
        cout<<"tm_mday: "<<tm.tm_mday<<endl;
        cout<<"tm_mon: "<<tm.tm_mon<<endl;
        cout<<"tm_year: "<<tm.tm_year<<endl;    
        cout<<"tm_wday: "<<tm.tm_wday<<endl;
        cout<<"tm_yday: "<<tm.tm_yday<<endl;

        time_t t = mktime(&tm);
        return t;
    }
int main() {
    time_t ans = convert_datetime_string_to_long_time("2023-03-02 00:00:00");
    cout<<ans<<endl;

    return 0;
}

这里的 ans =-1

这怎么可能???