# serial 11

# Copyright (C) 2003, 2007, 2009-2018 Free Software Foundation, Inc.

# This file is free software; the Free Software Foundation

# gives unlimited permission to copy and/or distribute it,

# with or without modifications, as long as this notice is preserved.

# See if we have a working tzset function.

# If so, arrange to compile the wrapper function.

# For at least Solaris 2.5.1 and 2.6, this is necessary

# because tzset can clobber the contents of the buffer

# used by localtime.

# Written by Paul Eggert and Jim Meyering.

AC_DEFUN([gl_FUNC_TZSET],

[

  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])

  AC_REQUIRE([gl_LOCALTIME_BUFFER_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST])

  AC_CHECK_FUNCS_ONCE([tzset])

  if test $ac_cv_func_tzset = no; then

    HAVE_TZSET=0

  fi

  gl_FUNC_TZSET_CLOBBER

  REPLACE_TZSET=0

  case "$gl_cv_func_tzset_clobber" in

    *yes)

      REPLACE_TZSET=1

      AC_DEFINE([TZSET_CLOBBERS_LOCALTIME], [1],

        [Define if tzset clobbers localtime's static buffer.])

      gl_LOCALTIME_BUFFER_NEEDED

      ;;

  esac

  case "$host_os" in

    mingw*) REPLACE_TZSET=1 ;;

  esac

])

# Set gl_cv_func_tzset_clobber.

AC_DEFUN([gl_FUNC_TZSET_CLOBBER],

[

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  AC_CACHE_CHECK([whether tzset clobbers localtime buffer],

                 [gl_cv_func_tzset_clobber],

    [AC_RUN_IFELSE([AC_LANG_SOURCE([[

#include <time.h>

#include <stdlib.h>

int

main ()

{

  time_t t1 = 853958121;

  struct tm *p, s;

  putenv ("TZ=GMT0");

  p = localtime (&t1;;

  s = *p;

  putenv ("TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00");

  tzset ();

  return (p->tm_year != s.tm_year

          || p->tm_mon != s.tm_mon

          || p->tm_mday != s.tm_mday

          || p->tm_hour != s.tm_hour

          || p->tm_min != s.tm_min

          || p->tm_sec != s.tm_sec);

}

  ]])],

       [gl_cv_func_tzset_clobber=no],

       [gl_cv_func_tzset_clobber=yes],

       [case "$host_os" in

                         # Guess all is fine on glibc systems.

          *-gnu* | gnu*) gl_cv_func_tzset_clobber="guessing no" ;;

                         # Guess no on native Windows.

          mingw*)        gl_cv_func_tzset_clobber="guessing no" ;;

                         # If we don't know, assume the worst.

          *)             gl_cv_func_tzset_clobber="guessing yes" ;;

        esac

       ])

    ])

  AC_DEFINE([HAVE_RUN_TZSET_TEST], [1],

    [Define to 1 if you have run the test for working tzset.])

])