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19991230: Y2K Bug Fix for pqact program of the LDM (fwd)

Subject: 19991230: Y2K Bug Fix for pqact program of the LDM


Hi,

A copy of this notice is available at

  http://www.unidata.ucar.edu/packages/ldm/y2k-fix.html

Thanks to Al Taylor of NOAA's Air Resources Laboratory for being the
first to report a Y2K bug in the pqact program of the LDM (all
versions). The symptom of the bug is that pqact.conf entries that make
use of two-digit year substitution patterns such as (\1:yy) will
substitute the string "10" instead of the string "00" for products
whose WMO header indicates a date in January or later.

For example, the pqact.conf entry 

WMO     ^S[AP][AC-Z][A-Z].* .... ([0-3][0-9])
        FILE    data/obs/surface/hrly/(\1:yy)(\1:mm)\1.hrly

when presented with a matching product with a date component of 010212
(representing 1200 on January 2) will append the product to a file
with a name such as "100212.hrly" instead of the expected
"000212.hrly".

A fix for the bug is to change line 643 in the source file
ldm-5.0.8/src/pqact/palt.c from

                (void) sprintf(ostring,"%d",year);

to 

                (void) sprintf(ostring,"%02d", year % 100);

and then rebuild pqact and reinstall it. An already-patched version of
the palt.c file is available from

  ftp://ftp.unidata.ucar.edu/pub/ldm5/palt.c.

To make it easier to install this bug fix, we have built new versions
of pqact for all the common platforms for which we make binary
distributions. You can just FTP the appropriate version of pqact for
your platform and install it in /usr/local/ldm/bin/pqact (or wherever
you have pqact installed). Below is a list of the available pqact
binaries. Versions built for an earlier version of a platform, for
example sunos_5.6-sparc, will generally work on later versions of the
same platform such as sunos_5.7-sparc.

  ftp://ftp.unidata.ucar.edu/pub/binary/aix_4.3-rs6000/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/hpux_10.20-hp9000/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/hpux_11.00-hp9000/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/irix64_6.5-mips/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/irix_6.5-mips/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/linux_2.2.5-i686/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/osf1_4.0-alpha/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/sunos_5.6-sparc/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/sunos_5.7-i86pc/pqact
  ftp://ftp.unidata.ucar.edu/pub/binary/sunos_5.7-sparc/pqact

If you have a platform for which none of these binaries is appropriate
or if you need pqact built with the GDBM option, you will have to
build a new version of pqact from source after making the one-line
change above. Here's how to do that:

% cd ~ldm/runtime/src/pqact
% mv palt.c palt.sav

Then copy the new palt.c to this directory. 

% make
% cp pqact ~ldm/bin

We will be happy to assist with this and give top priority to any
questions about this sent to address@hidden.

We're sorry for the inconvenience and the late notice on this bug, but
it slipped by our testing.


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