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emacs/lib/strftime.h
Paul Eggert 59fbaca6b9 Update from Gnulib by running admin/merge-gnulib
* admin/merge-gnulib (GNULIB_MODULES): Add stringeq.
With current Gnulib it is already present as in indirect dependency;
listing it here because Emacs now depends on it directly.
* lib-src/ebrowse.c, lib-src/etags.c:
(streq): Remove, as Gnulib defines this now.
* lib/fseterr.c, lib/fseterr.h, lib/issymlink.c, lib/issymlink.h:
* lib/issymlinkat.c, lib/stdio-consolesafe.c, lib/string.c:
* m4/fseterr.m4, m4/gettext_h.m4, m4/stringeq.m4:
New files from Gnulib.
* src/conf_post.h (tzfree) [__ANDROID_API__ >= 35]: Remove.
2025-11-04 13:32:58 -08:00

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C

/* declarations for strftime.c
Copyright (C) 2002, 2004, 2008-2025 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <stddef.h>
#include <time.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Format the broken-down time *__TP, with additional __NS nanoseconds,
into the buffer __S of size __MAXSIZE, according to the rules of the
LC_TIME category of the current locale.
Use the time zone __TZ.
If *__TP represents local time, __TZ should be set to
tzalloc (getenv ("TZ")).
If *__TP represents universal time (a.k.a. GMT), __TZ should be set to
(timezone_t) 0.
The format string __FORMAT, including GNU extensions, is described in
the GNU libc's strftime() documentation:
<https://www.gnu.org/software/libc/manual/html_node/Formatting-Calendar-Time.html>
Additionally, the following conversion is supported:
%N The number of nanoseconds, passed as __NS argument.
Here's a summary of the available conversions (= format directives):
literal characters %n %t %%
date:
century %C
year %Y %y
week-based year %G %g
month (in year) %m %B %b %h
week in year %U %W %V
day in year %j
day (in month) %d %e
day in week %u %w %A %a
year, month, day %x %F %D
time:
half-day %p %P
hour %H %k %I %l
minute (in hour) %M
hour, minute %R
second (in minute) %S
hour, minute, second %r %T %X
second (since epoch) %s
date and time: %c
time zone: %z %Z
nanosecond %N
In locales with non-Gregorian calendars, the following conversions don't
apply in the expected way:
date:
century %C
year %y
week-based year %G %g
week in year %U %W %V
day in year %j
year, month, day %D
Store the result, as a string with a trailing NUL character, at the
beginning of the array __S[0..__MAXSIZE-1] and return the length of
that string, not counting the trailing NUL.
If unsuccessful, possibly change the array __S, set errno, and return -1;
errno == ERANGE means the string didn't fit.
As a glibc extension if __S is null, do not store anything, and
return the value that would have been returned had __S been non-null.
A __MAXSIZE greater than PTRDIFF_MAX is silently treated as if
it were PTRDIFF_MAX, so that the caller can safely add 1 to
any return value without overflow.
This function is like strftime, but with two more arguments:
* __TZ instead of the local timezone information,
* __NS as the number of nanoseconds in the %N directive,
and on success it does not preserve errno,
and on failure it returns -1 not 0.
*/
ptrdiff_t nstrftime (char *restrict __s, size_t __maxsize,
char const *__format,
struct tm const *__tp, timezone_t __tz, int __ns);
/* Like nstrftime, except that it uses the "C" locale instead of the
current locale. */
ptrdiff_t c_nstrftime (char *restrict __s, size_t __maxsize,
char const *__format,
struct tm const *__tp, timezone_t __tz, int __ns);
#ifdef __cplusplus
}
#endif