Hi, strptime.3 claims %F is both ISO 8601 compliant and equivalent to %Y-%m-%d. Since the standard permits a leading dash character to indicate negative years [0], this can’t be both true. %F with strftime prints negative years just fine though. Hence I’m not sure if this is a bug in the docs or glibc. Best, Philipp [0] http://www.loc.gov/standards/datetime/iso-tc154-wg5_n0039_iso_wd_8601-2_2016-02-16.pdf
From 57818307dc9ad8ecebc9517c26f800d3ae0cb0de Mon Sep 17 00:00:00 2001
From: Philipp Gesang <phg@xxxxxxxxxxxxx>
Date: Sun, 19 Nov 2017 20:34:59 +0100
Subject: [PATCH] strptime.3: clarify behavior of %F with negative years
ISO 8601 explicitly allows for negative years:
year = positiveYear | negativeYear | "0000" ;
positiveYear = positiveDigit, digit, digit, digit
| ...
negativeYear = "-", positiveYear ;
Thus for strptime, "%F" isn't strictly equivalent to the ISO 8601 year
format since it fails to handle the sign. (strftime "%F" has no problem
with negative years.)
Signed-off-by: Philipp Gesang <phg@xxxxxxxxxxxxx>
---
man3/strptime.3 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/man3/strptime.3 b/man3/strptime.3
index 6a82b04f4..b261e0736 100644
--- a/man3/strptime.3
+++ b/man3/strptime.3
@@ -363,7 +363,7 @@ This leads to
.B %F
Equivalent to
.BR %Y-%m-%d ,
-the ISO 8601 date format.
+the ISO 8601 date format. (Parses only nonnegative year numbers.)
.TP
.B %g
The year corresponding to the ISO week number, but without the century
--
2.15.0
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