[PATCH 3/3] libc: Replace one letter member names in __tzrule_struct
Jeff Johnston
jjohnstn@redhat.com
Fri Oct 2 21:04:45 GMT 2020
On Fri, Oct 2, 2020 at 3:36 AM Torbjorn SVENSSON <torbjorn.svensson@st.com>
wrote:
> Hello!
>
> Thanks for the feedback Jeff.
>
> Regarding the alternative to using "__" prefix for the members; would it
> be better to move line 105-123 from newlib/libc/include/time.h to
> newlib/libc/time/local.h, thus not exposing it in the API?
>
Yes. It was one of the alternatives I mentioned (hiding the struct from
users of time.h). The struct is hidden in glibc and should have been
hidden likewise in newlib.
The lines in question are:
> typedef struct __tzrule_struct
> {
> char ch;
> int m;
> int n;
> int d;
> int s;
> time_t change;
> long offset; /* Match type of _timezone. */
> } __tzrule_type;
>
> typedef struct __tzinfo_struct
> {
> int __tznorth;
> int __tzyear;
> __tzrule_type __tzrule[2];
> } __tzinfo_type;
>
> __tzinfo_type *__gettzinfo (void);
>
>
>
> Would this change be easier to get accepted? If this approach is better, I
> guess the single letter member names can be kept too…
> While I took another look at the change, I also noticed that the struct
> definition (not usage) is also present in these files:
> newlib/libc/sys/linux/include/time.h
> newlib/libc/sys/phoenix/include/time.h
>
> I’m not sure in what situations those files are used and when the time.h
> file that I modified is used, but I guess they should be in sync regardless.
>
> Thanks
> Torbjörn
>
> From: Jeff Johnston <jjohnstn@redhat.com>
> Sent: den 2 oktober 2020 01:21
> To: Torbjorn SVENSSON <torbjorn.svensson@st.com>
> Cc: Newlib <newlib@sourceware.org>
> Subject: Re: [PATCH 3/3] libc: Replace one letter member names in
> __tzrule_struct
>
> Hello, while I fully agree there is an issue (the struct was due to my
> initial check-in in 2005 based on glibc), the change will break API and
> thus technically requires a major release bump of newlib. I would prefer
> to wait for something else
> to require a major bump before making such a change. In such a case, I
> also believe that the patch should either use double-underscores for the
> field names (e.g. __month) or hide the struct from regular users of time.h.
>
> -- Jeff J.
>
> On Thu, Oct 1, 2020 at 10:19 AM Torbjörn SVENSSON via Newlib <mailto:
> newlib@sourceware.org> wrote:
> As discussed in GCC bug 97088
> (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97088), parameters in
> prototypes of library functions should use reserved names, or no name
> at all.
>
> This patch replaces 'm', 'n', 'd' and 's' members in
> 'struct __tzrule_struct' to avoid possible clashes with user code in
> case someone uses before including Newlib's time.h (or uses some
> other conflicting definition)
>
> Signed-off-by: Torbjörn SVENSSON <mailto:torbjorn.svensson@st.com>
> ---
> newlib/libc/include/time.h | 8 ++++----
> newlib/libc/time/tzcalc_limits.c | 14 +++++++-------
> newlib/libc/time/tzset_r.c | 22 +++++++++++-----------
> 3 files changed, 22 insertions(+), 22 deletions(-)
>
> diff --git a/newlib/libc/include/time.h b/newlib/libc/include/time.h
> index 3031590b4..6a540537f 100644
> --- a/newlib/libc/include/time.h
> +++ b/newlib/libc/include/time.h
> @@ -105,10 +105,10 @@ void _tzset_r (struct _reent *);
> typedef struct __tzrule_struct
> {
> char ch;
> - int m;
> - int n;
> - int d;
> - int s;
> + int month; /* Month of year if ch=M */
> + int week; /* Week of month if ch=M */
> + int day; /* Day of week if ch=M, day of year if ch=J or ch=D */
> + int secs; /* Time of day in seconds */
> time_t change;
> long offset; /* Match type of _timezone. */
> } __tzrule_type;
> diff --git a/newlib/libc/time/tzcalc_limits.c
> b/newlib/libc/time/tzcalc_limits.c
> index e0ea6549c..b2163ed3d 100644
> --- a/newlib/libc/time/tzcalc_limits.c
> +++ b/newlib/libc/time/tzcalc_limits.c
> @@ -34,13 +34,13 @@ __tzcalc_limits (int year)
> if (tz->__tzrule[i].ch == 'J')
> {
> /* The Julian day n (1 <= n <= 365). */
> - days = year_days + tz->__tzrule[i].d +
> - (isleap(year) && tz->__tzrule[i].d >= 60);
> + days = year_days + tz->__tzrule[i].day +
> + (isleap(year) && tz->__tzrule[i].day >= 60);
> /* Convert to yday */
> --days;
> }
> else if (tz->__tzrule[i].ch == 'D')
> - days = year_days + tz->__tzrule[i].d;
> + days = year_days + tz->__tzrule[i].day;
> else
> {
> const int yleap = isleap(year);
> @@ -49,15 +49,15 @@ __tzcalc_limits (int year)
>
> days = year_days;
>
> - for (j = 1; j < tz->__tzrule[i].m; ++j)
> + for (j = 1; j < tz->__tzrule[i].month; ++j)
> days += ip[j-1];
>
> m_wday = (EPOCH_WDAY + days) % DAYSPERWEEK;
>
> - wday_diff = tz->__tzrule[i].d - m_wday;
> + wday_diff = tz->__tzrule[i].day - m_wday;
> if (wday_diff < 0)
> wday_diff += DAYSPERWEEK;
> - m_day = (tz->__tzrule[i].n - 1) * DAYSPERWEEK + wday_diff;
> + m_day = (tz->__tzrule[i].week - 1) * DAYSPERWEEK + wday_diff;
>
> while (m_day >= ip[j-1])
> m_day -= DAYSPERWEEK;
> @@ -67,7 +67,7 @@ __tzcalc_limits (int year)
>
> /* store the change-over time in GMT form by adding offset */
> tz->__tzrule[i].change = days * SECSPERDAY +
> - tz->__tzrule[i].s + tz->__tzrule[i].offset;
> + tz->__tzrule[i].secs + tz->__tzrule[i].offset;
> }
>
> tz->__tznorth = (tz->__tzrule[0].change < tz->__tzrule[1].change);
> diff --git a/newlib/libc/time/tzset_r.c b/newlib/libc/time/tzset_r.c
> index 9e0cf834b..7117b51e6 100644
> --- a/newlib/libc/time/tzset_r.c
> +++ b/newlib/libc/time/tzset_r.c
> @@ -115,9 +115,9 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
> return;
>
> tz->__tzrule[i].ch = 'M';
> - tz->__tzrule[i].m = m;
> - tz->__tzrule[i].n = w;
> - tz->__tzrule[i].d = d;
> + tz->__tzrule[i].month = m;
> + tz->__tzrule[i].week = w;
> + tz->__tzrule[i].day = d;
>
> tzenv += n;
> }
> @@ -142,22 +142,22 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
> if (i == 0)
> {
> tz->__tzrule[0].ch = 'M';
> - tz->__tzrule[0].m = 3;
> - tz->__tzrule[0].n = 2;
> - tz->__tzrule[0].d = 0;
> + tz->__tzrule[0].month = 3;
> + tz->__tzrule[0].week = 2;
> + tz->__tzrule[0].day = 0;
> }
> else
> {
> tz->__tzrule[1].ch = 'M';
> - tz->__tzrule[1].m = 11;
> - tz->__tzrule[1].n = 1;
> - tz->__tzrule[1].d = 0;
> + tz->__tzrule[1].month = 11;
> + tz->__tzrule[1].week = 1;
> + tz->__tzrule[1].day = 0;
> }
> }
> else
> {
> tz->__tzrule[i].ch = ch;
> - tz->__tzrule[i].d = d;
> + tz->__tzrule[i].day = d;
> }
>
> tzenv = end;
> @@ -172,7 +172,7 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
> if (*tzenv == '/')
> sscanf (tzenv, "/%hu%n:%hu%n:%hu%n", &hh, &n, &mm, &n, &ss, &n);
>
> - tz->__tzrule[i].s = ss + SECSPERMIN * mm + SECSPERHOUR * hh;
> + tz->__tzrule[i].secs = ss + SECSPERMIN * mm + SECSPERHOUR * hh;
>
> tzenv += n;
> }
> --
> 2.18.0
>
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