Re: [boost] boost::gregorian::to_tm() initializes some fields of struct tm, but not all

Subject: Re: [boost] boost::gregorian::to_tm() initializes some fields of struct tm, but not all
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2009-02-07 09:46:13

Dmitry Goncharov wrote:
> Hi,
> 
> boost::gregorian::to_tm() initializes some fields of struct tm, but not 
> all. Implementations keep there additional fields.
> Besides the fields defined by POSIX libc2.9 has two additional fields in 
> struct tm:
> struct tm
> {
> ...
> #ifdef    __USE_BSD
>  long int tm_gmtoff;        /* Seconds east of UTC.  */
>  __const char *tm_zone;    /* Timezone abbreviation.  */
> #else
>  long int __tm_gmtoff;        /* Seconds east of UTC.  */
>  __const char *__tm_zone;    /* Timezone abbreviation.  */
> #endif
> };
> 
> There are two additional fields tm_gmtoff and tm_zone.
> boost::gregorian::to_tm() does not initialize tm_zone and tm_gmtoff.
> There are functions as well which use these additional fields.
> E.g. this is a piece of code from the implementation of strftime() from 
> libc2.9:
> 
> static size_t
> __strftime_internal (s, maxsize, format, tp, tzset_called ut_argument
> ...
> {
> ...
>  zone = (const char *) tp->tm_zone;
> #endif
> #if HAVE_TZNAME
>  if (ut)
>    {
>      if (! (zone && *zone))
>    zone = "GMT";
>    }
> ...
> }
> This function dereferences tp->tm_zone.
> 
> I have not created a ticker since this could be an already known issue.

I believe, this is mentioned here:

https://svn.boost.org/trac/boost/ticket/1859

This issue is not fixed yet.