Hi, наб and Branden! On 7/19/22 03:56, наб wrote:
FreeBSD timezone(3) is V7 char *timezone(int zone, int dst), our documentation would imply it's impossible to service this type of system portably Indeed, glibc defines them both, and they make more sense for most use-cases than trying to use the globals
Great!
glibc cited for __USE_MISC, tm_zone invalidation is Debian 2.33-7
But I guess it is present in much older glibcs, right? Otherwise we should add a VERSIONS thingy.
POSIX cited for XSI marking is Issue 7 TC2
CSRG CD #2 contains 4.3BSD-Tahoe with both members
This also fixes the multiple lies in man-pages 5.10 localtime(3),
which says only:
The glibc version of struct tm has additional fields
const char *tm_zone; /* Timezone abbreviation */
defined when _BSD_SOURCE was set before including <time.h>.
This is a BSD extension, present in 4.3BSD-Reno.
Did you forget that removal of lies? I don't see it in the patch.
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx> --- man3/tm.3type | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/man3/tm.3type b/man3/tm.3type index 1931d890d..8b6f8d9bf 100644 --- a/man3/tm.3type +++ b/man3/tm.3type @@ -25,8 +25,26 @@ Standard C library .BR " int tm_yday;" \ " /* Day of the year [" 0 ", " 365 "] (Jan/01 = " 0 ") */" .BR " int tm_isdst;" " /* Daylight savings flag */" + +.BR " long tm_gmtoff;" " /* Seconds East of UTC */" +.BR " char*tm_zone;" " /* Timezone abbreviation */"
Please add cosmetic whitespace (at least 1 for every member, possibly 2, depending on your taste) :)
.B }; .fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.IR tm_gmtoff , +.IR tm_zone : +.nf +.\" Guarded with __USE_MISC: + Since glibc 2.19: + _DEFAULT_SOURCE + Glibc 2.19 and earlier: + _BSD_SOURCE || _SVID_SOURCE +.fi .SH DESCRIPTION Describes time, broken down into distinct components. .PP @@ -35,6 +53,16 @@ describes wether daylight saving time is in effect at the time described. The value is positive if daylight saving time is in effect, zero if it is not, and negative if the information is not available. +.PP +.I tm_gmtoff +is the difference, in seconds, of the timezone represented by this broken-down time and UTC +(this is the reverse of
Could you come up with a more mathematically precise term for "reverse"? What is reverse? The additive inverse? Maybe use "additive inverse"? I think "opposite" also has the meaning of additive inverse in maths, and it's maybe a simpler term (although additive inverse is more precise, IMHO). But reverse is definitely confusing to me.
+.BR timezone (3)). +.PP +.I tm_zone +is the equivalent of +.BR tzname (3) +for the timezone represented by this broken-down time. .SH VERSIONS In C90, .I tm_sec @@ -48,10 +76,27 @@ in C99. .SH CONFORMING TO C90 and later; POSIX.1-2001 and later. +.PP +.IR tm_gmtoff " and " tm_zone +originate from 4.3BSD-Tahoe. .SH NOTES .I tm_sec can represent a leap second with the value .BR 60 . +.PP +.BR timezone (3), +as a variable, is an XSI extension \(em some systems provide the V7-compatible
I tend to prefer the em dash to be next to (no whitespace) the enclosed clause. That makes it easier to mentally associate (as in a set of parentheses) to the clause. I'm not sure if it's a thing of mine, or if it's standard practise?
+.\" FreeBSD +.BR timezone () +function. +The +.I tm_gmtoff +fields provides an alternative (with the opposite sign) for those systems. +.PP +.I tm_zone +points to potentially-constant static storage and may be overriden on subsequent calls to +.BR localtime (3) +&a. (this, however, never happens under glibc).
What is "&a."? Is that documented somewhere? I didn't know that abbreviature.
Keep in mind man-pages(7):
Use of e.g., i.e., etc., a.k.a., and similar
In general, the use of abbreviations such as "e.g.",
"i.e.", "etc.", "cf.", and "a.k.a." should be avoided, in
favor of suitable full wordings ("for example", "that
is", "and so on", "compare to", "also known as").
The only place where such abbreviations may be acceptable
is in short parenthetical asides (e.g., like this one).
Always include periods in such abbreviations, as shown
here. In addition, "e.g." and "i.e." should always be
followed by a comma.
BTW, if the '.' is not a sentence ending, it might be good to mark it
with the ineffable \& escape :)
&a.\& (this ...
.SH SEE ALSO .BR ctime (3), .BR strftime (3),
-- Alejandro Colomar <http://www.alejandro-colomar.es/>
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