如何使用c ++在linux中获取utc偏移量

Question

我正在使用以下代码段来计算utc偏移量,但我发现有时会返回错误的结果:

double DateTime::getUTCOffset()
{
    time_t currtime;

    struct tm * timeinfo;



    time ( &currtime );

    timeinfo = gmtime ( &currtime );

    time_t utc = mktime( timeinfo );

    timeinfo = localtime ( &currtime );

    time_t local = mktime( timeinfo );



    // Get offset in hours from UTC

    double offsetFromUTC = ((difftime(local, utc) / HOUR_IN_SECONDS) );

    // Adjust for DST

    if (timeinfo->tm_isdst)
    {
        offsetFromUTC += 1;
    }
    return offsetFromUTC;
}

%90%的时候它是正确的,计算utc偏移量的最佳方法是什么？

Answer 1

我认为该tm_gmtoff字段应该在您的系统上可用.

std::time_t current_time;
std::time(&current_time);
struct std::tm *timeinfo = std::localtime(&current_time);
long offset = timeinfo->tm_gmtoff;