bug in Localtime

[p5pRT]

Migrated from rt.perl.org#1740 (status was 'resolved')

Searchable as RT1740$

[p5pRT]

From rbroeck@new-edc.nl

I found a problem using the function localtime. Executing the below script
will give me a wrong value for $mon (10 i.s.o. 11)​:

($sec,$min,$hour,$day,$mon,$year,$wday,$yday,$isdst) = localtime(time) ;
printf "$year/$mon/$day\n";
printf "$hour​:$min​:$sec\n";
printf "$]\n";

output​:

99/10/3
12​:12​:2
5.00503

using the functions date and time (MSDOS box under Windows NT 4)

Date​: wo 03-11-1999
time​: 12​:12​:02,32

Is this a bug in Perl ?

perl -V gives you​:

Summary of my perl5 (5.0 patchlevel 5 subversion 03) configuration​:
  Platform​:
  osname=MSWin32, osvers=4.0, archname=MSWin32-x86-object
  uname=''
  hint=recommended, useposix=true, d_sigaction=undef
  usethreads=undef useperlio=undef d_sfio=undef
  Compiler​:
  cc='cl.exe', optimize='-O2 -MD -DNDEBUG -TP -GX', gccversion=
  cppflags='-DWIN32'
  ccflags ='-O2 -MD -DNDEBUG -TP -GX -DWIN32 -D_CONSOLE -DNO_STRICT
-DHAVE_DES_FCRYPT -DPERL_OBJECT'
  stdchar='char', d_stdstdio=define, usevfork=false
  intsize=4, longsize=4, ptrsize=4, doublesize=8
  d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=10
  alignbytes=8, usemymalloc=n, prototype=define
  Linker and Libraries​:
  ld='link', ldflags ='-nologo -nodefaultlib -release -machine​:x86'
  libpth="C​:\Perl\lib\core"
  libs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib
uuid.lib wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib
PerlCRT.lib
  libc=C​:\Perl\lib\CORE\PerlCRT.lib, so=dll, useshrplib=yes,
libperl=perlcore.lib
  Dynamic Linking​:
  dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
  cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -release
-machine​:x86'

Characteristics of this binary (from libperl)​:
  Locally applied patches​:
  ActivePerl Build 519
  Built under MSWin32
  Compiled at Aug 12 1999 09​:50​:30
  @​INC​:
  c​:/Perl/lib
  c​:/Perl/site/lib
  .
Rob Van den Broeck
New EDC BV

e-mail​: mailto​:rbroeck@​new-edc.nl
www : http​://www.new-edc.nl

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[p5pRT]

From [Unknown Contact. See original ticket]

Rob van den Broeck <rbroeck@​new-edc.nl> writes​:

I found a problem using the function localtime. Executing the below script
will give me a wrong value for $mon (10 i.s.o. 11)​:

($sec,$min,$hour,$day,$mon,$year,$wday,$yday,$isdst) = localtime(time) ;
printf "$year/$mon/$day\n";
printf "$hour​:$min​:$sec\n";
printf "$]\n";

output​:

99/10/3
12​:12​:2
5.00503

=item localtime EXPR

Converts a time as returned by the time function to a 9-element array
with the time analyzed for the local time zone. Typically used as
follows​:

  # 0 1 2 3 4 5 6 7 8
  ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
  localtime(time);

All array elements are numeric, and come straight out of a struct tm. In
particular this means that C<$mon> has the range C<0..11> and C<$wday> has
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
the range C<0..6> with sunday as day C<0>. Also, C<$year> is the number
of years since 1900, that is, C<$year> is C<123> in year 2023, and I<not>
simply the last two digits of the year.

If EXPR is omitted, uses the current time (C<localtime(time)>).

In scalar context, returns the ctime(3) value​:

  $now_string = localtime; # e.g., "Thu Oct 13 04​:54​:34 1994"

This scalar value is B<not> locale dependent, see L<perllocale>, but
instead a Perl builtin. Also see the C<Time​::Local> module, and the
strftime(3) and mktime(3) function available via the POSIX module. To get
somewhat similar but locale dependent date strings, set up your locale
environment variables appropriately (please see L<perllocale>) and try for
example​:

  use POSIX qw(strftime);
  $now_string = strftime "%a %b %e %H​:%M​:%S %Y", localtime;

Note that the C<%a> and C<%b>, the short forms of the day of the week and
the month of the year, may not necessarily be three characters wide.

--
Russ Allbery (rra@​stanford.edu) <URL​:http​://www.eyrie.org/~eagle/>