time/asctime.c

   1 /* Copyright (C) 1991, 1993, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include "../locale/localeinfo.h"
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <time.h>
  24
  25
  26 /* Returns a string of the form "Day Mon dd hh:mm:ss yyyy\n"
  27    which is the representation of TP in that form.  */
  28 char *
  29 DEFUN(asctime, (tp), CONST struct tm *tp)
  30 {
  31   static const char format[] = "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n";
  32   static char result[            3+1+ 3+1+20+1+20+1+20+1+20+1+20+1 + 1];
  33
  34   if (tp == NULL)
  35     {
  36       errno = EINVAL;
  37       return NULL;
  38     }
  39
  40   if (sprintf (result, format,
  41                (tp->tm_wday < 0 || tp->tm_wday >= 7 ?
  42                 "???" : _NL_CURRENT (LC_TIME, ABDAY_1 + tp->tm_wday)),
  43                (tp->tm_mon < 0 || tp->tm_mon >= 12 ?
  44                 "???" : _NL_CURRENT (LC_TIME, ABMON_1 + tp->tm_mon)),
  45                tp->tm_mday, tp->tm_hour, tp->tm_min,
  46                tp->tm_sec, 1900 + tp->tm_year) < 0)
  47     return NULL;
  48
  49   return result;
  50 }