kc3-lang/gnulib/lib/wcsftime.c

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• Hash : 7b089321
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  Date : 2025-01-01T09:24:36
  

  maint: run 'make update-copyright'
  

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• lib/wcsftime.c

• /* Work around platform bugs in wcsftime.
     Copyright (C) 2017-2025 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 2.1 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 <config.h>
  
  /* Specification.  */
  #include <wchar.h>
  
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  
  #undef wcsftime
  
  size_t
  rpl_wcsftime (wchar_t *buf, size_t bufsize, const wchar_t *format, const struct tm *tp)
  {
  #if defined _WIN32 && ! defined __CYGWIN__
    /* Rectify the value of the environment variable TZ.
       There are four possible kinds of such values:
         - Traditional US time zone names, e.g. "PST8PDT".  Syntax: see
           <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/tzset>
         - Time zone names based on geography, that contain one or more
           slashes, e.g. "Europe/Moscow".
         - Time zone names based on geography, without slashes, e.g.
           "Singapore".
         - Time zone names that contain explicit DST rules.  Syntax: see
           <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03>
       The Microsoft CRT understands only the first kind.  It produces incorrect
       results if the value of TZ is of the other kinds.
       But in a Cygwin environment, /etc/profile.d/tzset.sh sets TZ to a value
       of the second kind for most geographies, or of the first kind in a few
       other geographies.  If it is of the second kind, neutralize it.  For the
       Microsoft CRT, an absent or empty TZ means the time zone that the user
       has set in the Windows Control Panel.
       If the value of TZ is of the third or fourth kind -- Cygwin programs
       understand these syntaxes as well --, it does not matter whether we
       neutralize it or not, since these values occur only when a Cygwin user
       has set TZ explicitly; this case is 1. rare and 2. under the user's
       responsibility.  */
    const char *tz = getenv ("TZ");
    if (tz != NULL && strchr (tz, '/') != NULL)
      {
        /* Neutralize it, in a way that is multithread-safe.
           (If we were to use _putenv ("TZ="), it would free the memory allocated
           for the environment variable "TZ", and thus other threads that are
           using the previously fetched value of getenv ("TZ") could crash.)  */
        char **env = _environ;
        wchar_t **wenv = _wenviron;
        if (env != NULL)
          for (char **ep = env; *ep != NULL; ep++)
            {
              char *s = *ep;
              if (s[0] == 'T' && s[1] == 'Z' && s[2] == '=')
                s[0] = '$';
            }
        if (wenv != NULL)
          for (wchar_t **wep = wenv; *wep != NULL; wep++)
            {
              wchar_t *ws = *wep;
              if (ws[0] == L'T' && ws[1] == L'Z' && ws[2] == L'=')
                ws[0] = L'$';
            }
      }
  #endif
  
    return wcsftime (buf, bufsize, format, tp);
  }
  

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