From K.McManus@gre.ac.uk

Created by k.mcmanus@gre.ac.uk

Documentation for localtime says...

  "$isdst is true if the specified time occurs during daylight savings
  time, false otherwise."

Unless I am mistaken this is not the case.
I get the same effect on my 5.005_03 built for i386-linux.

HTH

Site configuration information for perl 5.00503:

Configured by ds19 at Mon Feb 14 15:31:53 GMT 2000.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=solaris, osvers=2.5.1, archname=sun4-solaris
    uname='sunos gandhi 5.5.1 generic_103640-31 sun4u sparc sunw,ultra-1 '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='gcc -B/usr/ccs/bin/', optimize='-O3', gccversion=egcs-2.91.66 19990314 (egcs-1.1.2 release)
    cppflags='-I/usr/local/include'
    ccflags ='-I/usr/local/include'
    stdchar='unsigned char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    alignbytes=8, usemymalloc=y, prototype=define
  Linker and Libraries:
    ld='gcc -B/usr/ccs/bin/', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib
    libs=-lsocket -lnsl -ldl -lm -lc -lcrypt
    libc=/lib/libc.so, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-fPIC', lddlflags='-G -L/usr/local/lib'

Locally applied patches:
    


@INC for perl 5.00503:
    /pkg/perl-5.005_03/lib/5.00503/sun4-solaris
    /pkg/perl-5.005_03/lib/5.00503
    /pkg/perl-5.005_03/lib/site_perl/5.005/sun4-solaris
    /pkg/perl-5.005_03/lib/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/home/mk05
    LANG (unset)
    LANGUAGE (unset)
    LC_COLLATE=en_GB.ISO8859-1
    LC_CTYPE=en_GB.ISO8859-1
    LC_MESSAGES=C
    LC_MONETARY=en_GB.ISO8859-1
    LC_NUMERIC=en_GB.ISO8859-1
    LC_TIME=en_GB.ISO8859-1
    LD_LIBRARY_PATH=/usr/lib:/usr/local/lib:/usr/local/gnu/lib:/usr/lib:/usr/local/lib:/usr/local/gnu/lib:/usr/lib:/usr/local/lib:/usr/local/gnu/lib:/usr/openwin/lib
    LOGDIR (unset)
    PATH=/pkg/SUNWspro-4.2/bin:/pkg/tetex/bin/sparc-sun-solaris2.5.1:/home/mk05/bin:/home/mk05/bin/extra:.:/pkg/SUNWspro-4.2/bin:/pkg/tetex/bin/sparc-sun-solaris2.5.1:/home/mk05/bin:/home/mk05/bin/extra:.:/pkg/SUNWspro/bin:/usr/ccs/bin:/usr/openwin/bin:/usr/local/bin:/usr/bin:/usr/ucb:/usr/local/gnu/bin:.:/usr/sbin:/usr/local/bin:/usr/bin/X11:/pkg/captool/bin:/pkg/pvm-3.3.9/pvm3/lib:/pkg/pvm-3.3.9/pvm3/lib/SUNMP:/pkg/pvm-3.3.9/pvm3/bin/SUNMP:/home/lp01/work/psp/captool/bin:/pkg/mpich/bin:/pkg/mpich/lib/solaris/ch_p4:/home/mk05/bin/extra:/usr/local/bin:/usr/bin/X11:/pkg/captool/bin:/pkg/pvm-3.3.9/pvm3/lib:/pkg/pvm-3.3.9/pvm3/lib/SUNMP:/pkg/pvm-3.3.9/pvm3/bin/SUNMP:/home/lp01/work/psp/captool/bin:/pkg/mpich/bin:/pkg/mpich/lib/solaris/ch_p4:/home/mk05/bin/extra
    PERL_BADLANG (unset)
    SHELL=/usr/bin/tcsh

From K.McManus@gre.ac.uk

Bug discovered to be UK (lack of) understanding (US) DST

Apologies for unnecessary posting

k.mcmanus@​gre.ac.uk - http​://staffweb.cms.gre.ac.uk/~k.mcmanus

Dr Kevin McManus ||Queen Mary 413
School of Computing & Math Science ||
The University of Greenwich ||
Park Row, Greenwich ||Tel +44 (0)208 331 8719
London SE10 9LS UK ||Fax +44 (0)208 331 8665

From @iabyn

On Wed, Oct 30, 2002 at 04​:27​:02AM -0000, K.McManus@​gre.ac.uk (via RT) wrote​:

Documentation for localtime says...

"$isdst is true if the specified time occurs during daylight savings
time, false otherwise."

Unless I am mistaken this is not the case.
I get the same effect on my 5.005_03 built for i386-linux.

I believe you may be mistaken!

Bear in mind that the result is influenced by the TZ environment variable.
For example, try the following​:

$ cat /tmp/p
#!/usr/bin/perl -w
$t = time;
for (1..10) {
  print +(localtime($t))[8] ? 'dst ' : ' ', scalar(localtime($t)),
  "\n";
  $t -= 86400*365 / 2;
}

$ TZ=GB /tmp/p
  Wed Oct 30 22​:52​:12 2002
dst Wed May 1 11​:52​:12 2002
  Tue Oct 30 22​:52​:12 2001
dst Tue May 1 11​:52​:12 2001
  Mon Oct 30 22​:52​:12 2000
dst Mon May 1 11​:52​:12 2000
  Sun Oct 31 22​:52​:12 1999
dst Sun May 2 11​:52​:12 1999
  Sat Oct 31 22​:52​:12 1998
dst Sat May 2 11​:52​:12 1998

$ TZ=GMT /tmp/p
  Wed Oct 30 22​:52​:20 2002
  Wed May 1 10​:52​:20 2002
  Tue Oct 30 22​:52​:20 2001
  Tue May 1 10​:52​:20 2001
  Mon Oct 30 22​:52​:20 2000
  Mon May 1 10​:52​:20 2000
  Sun Oct 31 22​:52​:20 1999
  Sun May 2 10​:52​:20 1999
  Sat Oct 31 22​:52​:20 1998
  Sat May 2 10​:52​:20 1998

--
That he said that that that that is is is debatable, is debatable.

From K.McManus@gre.ac.uk

Hi Dave,

Bear in mind that at this time of year overworked academics make the most
blundering of errors - had i bothered to su root on linux and wind the
clock back I would have realised that... in the UK we speak of saving
daylight in winter but in the US - based on $isdst - i have to assume
that the US save daylight in summer.

Apologies for wasting precious time - weak pun

I take solace in seeing - from google trawl - that i am not the first to
stumble into this localisation error.

Bit pathetic as I write this sat on the Greenwich meridian - the very
origin of time.

Good point - I can confidently report superb bug tracking response from
Perl community to my students.

Regards

k.mcmanus@​gre.ac.uk - http​://staffweb.cms.gre.ac.uk/~k.mcmanus

Dr Kevin McManus ||Queen Mary 413
School of Computing & Math Science ||
The University of Greenwich ||
Park Row, Greenwich ||Tel +44 (0)208 331 8719
London SE10 9LS UK ||Fax +44 (0)208 331 8665

From @iabyn

not a bug.

@iabyn - Status changed from 'new' to 'resolved'