NAME
    Tie::Gzip - read and write gzip compressed files

SYNOPSIS
     require Tie::Gzip;

     tie filehandle, 'Tie::Gzip'
     tie filehandle, 'Tie::Gzip', mode, filename
     tie filehandle, 'Tie::Gzip', filename

     tie filehandle, 'Tie::Gzip', \%options
     tie filehandle, 'Tie::Gzip', mode, filename, \%options 
     tie filehandle, 'Tie::Gzip', filename, \%options

     tie filehandle, 'Tie::Gzip', \@options
     tie filehandle, 'Tie::Gzip', mode, filename, \@options 
     tie filehandle, 'Tie::Gzip', filename, \@options

DESCRIPTION
    The 'Tie::Gzip' module provides a file handle Tie for compressing and
    uncompressing files using the gzip compression format.

    By tieing a filehandle to 'Tie::Gzip' subsequent uses of the file
    subroutines with the tied filehandle will compress data written to an
    opened file using gzip compression and decompress data read from an
    opened file using gzip compression.

    If the 'Tie::Gzip' tie receives a *filename* or *mode filename* after
    completing the tie, 'Tie::Gzip' will open *filename*.

    During the tie, Tie::Gzip will first try to load the 'Compress::Zlib'
    module and package. If successful, 'Tie::Gzip' uses the 'Compress::Zlib'
    for compressing and decompressing the file data.

    If unsuccessful, 'Tie::Gzip' setups up the following pipes to an
    anticipated GNU 'gzip' site command for compressing and decompressing
    the file data:

     gzip --decompress --stdout {} | # read file data
     | gzip --stdout > {} # write file data

    where the string '{}' is a placeholder for the *filename*.

    Many sites, especially UNIX Internet Service Providers, will not provide
    the 'Compress::Zlib' module. Instead they expect the users to make use
    of a site Unix gzip command.

    If neither of these gzip resources are available for a site, 'Tie::Gzip'
    provides the 'read_pipe' and 'write_pipe' options, to tie to a suitable
    local site gzip command.

    For example, to specify the GNU gzip, provide the following options as
    either a hash or array reference:

     [ read_pipe => 'gzip --decompress --stdout {}',
       write_pipe => ' gzip --stdout > {}' ]

    The pipe symbol '|' is optional. The 'Tie::Gzip' uses the 'binmode' for
    all data to and from the read and write pipes. This is equivalent to
    'raw' (as oppose to 'cooked') for Unix file drivers and the binary (as
    oppose to 'text') for Windows file drivers.

    The hash reference to the 'Tie::Gzip' data may be obtained as follows:

      my $self = tied filehandle;
  
    The 'Tie::Gzip' data hash keys and contents are subject to change
    without notice expect for

      $self->{options}->{read_pipe}
      $self->{options}->{write_pipe}

    as described above.

    Because of the nature of the gzip compression software, the file
    subroutines have at least the following restrictions:

    open
        The open command will accept only the '>' and the '<' modes. All
        other modes are invalid. The 'Tie::Gzip' tie does provide greatly
        limited piping capabilities with the 'read_pipe' and 'write_pipe'
        options. Feature creep of reading and writing a compress file is
        coming.

    seek
        The seek is only valid for mode 1, positive seeks when reading a
        compress files. Feature creep of seek is comming.

    fileno
        The file no when using "Compress::Zlib" is undefined.

    binmode
        This subroutine does nothing since the tied 'Tie::Gzip' file handle
        is always in the binmode.

REQUIREMENTS
    For these requirements the pharse 'Tie Gzip file handle' will mean a
    file handle successfully tied to 'Tie::Gzip' that uses either the
    'Compress::Zlib' module or the a site system GNU gzip executable to
    compress and decompress the file data. Thus, the data written to a file
    using a 'Tie::Gzip file handle' should be in accordance with RFC 1951
    and RFC 1952.

    The 'Tie::Gzip' requirements are as follows:

    data integrity [1]
        The data read back from a file using a 'Tie::Gzip file handle'
        shall[1] be the same as the data written to the file using a
        'Tie::Gzip file handle'.

    interoperability [1]
        The data read back from a file using a software unit or executable
        program in accordance with RFC 1951 and RFC 1952 shall[1] be the
        same as the data written to the same file using a 'Tie::Gzip file
        handle'.

    interoperability [2]
        The data read back from a file using 'Tie::Gzip file handle shall[2]
        be the same as the data written to the same file using a software
        unit or executable program in accordance with RFC 1951 and RFC 1952.

DEMONSTRATION
     ~~~~~~ Demonstration overview ~~~~~

    Perl code begins with the prompt

     =>

    The selected results from executing the Perl Code follow on the next
    lines. For example,

     => 2 + 2
     4

     ~~~~~~ The demonstration follows ~~~~~

     =>     use File::Package;
     =>     use File::Copy;
     =>     use File::SmartNL;

     =>     my $uut = 'Tie::Gzip'; # Unit Under Test
     =>     my $fp = 'File::Package';
     =>     my $snl = 'File::SmartNL';
     =>     my $loaded;

     => ##################
     => # Load UUT
     => # 
     => ###

     => my $errors = $fp->load_package($uut)
     => $errors
     ''

     => ##################
     => # Tie::Gzip Verion $Tie::Gzip::VERSION
     => # 
     => ###

     => $Tie::Gzip::VERSION
     '1.12'

     =>       sub gz_decompress
     =>      {
     =>          my ($gzip) = shift @_;
     =>          my $file = 'gzip1.htm';
     =>  
     =>          return undef unless open($gzip, "< $file.gz");

     =>          if( open (FILE, "> $file" ) ) {
     =>              while( my $line = <$gzip> ) {
     =>                   print FILE $line;
     =>              }
     =>              close FILE;
     =>              close $gzip;
     =>              unlink 'gzip1.htm.gz';
     =>              return 1;
     =>          }

     =>          1 

     =>      }

     =>      sub gz_compress
     =>      {
     =>          my ($gzip) = shift @_;
     =>          my $file = 'gzip1.htm';
     =>          return undef unless open($gzip, "> $file.gz");
     =>         
     =>          if( open(FILE, "< $file") ) {
     =>              while( my $line = <FILE> ) {
     =>                     print $gzip $line;
     =>              }
     =>              close FILE;
     =>              unlink $file;
     =>          }
     =>          close $gzip;
     =>     }

     =>     #####
     =>     # Compress gzip1.htm with gzip software unit of opportunity
     =>     # Decompress gzip1.htm,gz with gzip software unit of opportunity
     =>     #
     =>     unlink 'gzip1.htm';
     =>     copy 'gzip0.htm', 'gzip1.htm';
     =>     tie *GZIP, 'Tie::Gzip';
     =>     my $tie_obj = tied *GZIP;
     =>     my $gz_package = $tie_obj->{gz_package};
     =>     my $gzip = \*GZIP;
     =>     
     =>     #####
     =>     # Do not skip tests 3 and 4 if this expression fails. Test 3 and 4 passing
     =>     # are mandatory to ensure at least one gzip is available and works
     =>     # 
     =>     my $gzip_opportunity= gz_compress( $gzip );

     => ##################
     => # Compress gzip1.htm with gzip of opportunity; Validate gzip1.htm.gz exists
     => # 
     => ###

     => -e 'gzip1.htm.gz'
     '1'

     => ##################
     => # Decompress gzip1.htm.gz with gzip of opportunity; Validate gzip1.htm
     => # 
     => ###

     => gz_decompress( $gzip )
     => $gzip_opportunity = $snl->fin( 'gzip1.htm') eq $snl->fin( 'gzip0.htm')
     '1'

     => ##################
     => # Compress gzip1.htm with site os GNU gzip. Validate gzip1.htm.gz exists
     => # 
     => ###

     =>     ##### 
     =>     # Compress gzip1.htm with site operating system GNU gzip
     =>     # Decompress gzip1.htm,gz with site GNU gzip
     =>     #
     =>     my $perl_gzip_success = 0;
     =>     my $os_gzip_success = 0;
     =>     if($gzip_opportunity) {
     =>         if(gz_package) {
     =>             $perl_gzip_success =1;
     =>             $os_gzip_success = 0;
     =>         }
     =>         else {
     =>             $perl_gzip_success =0;
     =>             $os_gzip_success = 1;
     =>         }
     =>     }
     =>     tie *GZIP, 'Tie::Gzip', {
     =>         read_pipe => 'gzip --decompress --stdout {}',
     =>         write_pipe => 'gzip --stdout > {}',
     =>     };
     =>     $gzip = \*GZIP;
     =>   
     =>     my $skip_flag = 0;
     =>     unless( gz_compress($gzip) ) {
     =>         $skip_flag = 1;
     =>         skip_tests( );
     =>     };
     => -e 'gzip1.htm.gz'
     '1'

     => ##################
     => # Decompress with site os GNU gzip. Validate gzip1.htm
     => # 
     => ###

     => gz_decompress( $gzip ) unless $skip_flag
     => $os_gzip_success = $snl->fin( 'gzip1.htm') eq $snl->fin( 'gzip0.htm')
     '1'

     => unlink 'gzip1.htm'

QUALITY ASSURANCE
  Test Script Design

    The "Tie:Gzip" test script performs multiple duties. The "Tie::Gzip"
    program module finds a gzip software unit of opportunity looking for
    both Perl "Compress::Zlib" program module and a site operating system
    gzip with the following GNU syntax:

     read_pipe => 'gzip --decompress --stdout {}',
     write_pipe => 'gzip --stdout > {}',

    If a particular site does not support both gzips, those tests, such as
    the interoperatability between different gzip software units, are
    skipped.

    For quality assurance, the "Tie::Gzip" test is performed on a site that
    supports both. For installation test, only one is needed for a pass.
    However if an installation supports both, both should pass in order to
    meet the interoperatability requirement for the "Tie::Gzip" module. This
    of course does not test that files produced from gzip software units
    outside the site are interoperatable. However, since the site gzip used
    for the quality assurance test meets the RFC 1951 and RFC 1952, the
    chances are that the gzip outside the site is broken if "Tie::Gzip"
    cannot decompress it.

    A test run example from "Tie-Gzip-0.04.tar.gz" follows:

     ==> perl gzip.t

     1..11
     # Running under perl version 5.006001 for MSWin32
     # Win32::BuildNumber 635
     # Current time local: Thu Apr 15 01:39:55 2004
     # Current time GMT:   Thu Apr 15 05:39:55 2004
     # Using Test.pm version 1.24
     # Test::Tech    : 1.18
     # Data::Secs2   : 1.16
     # =cut 
     ok 1 - UUT not loaded 
     ok 2 - Load UUT 
     ok 3 - Tie::Gzip Verion 1.12 
     ok 4 - Compress gzip1.htm with gzip of opportunity; Validate gzip1.htm.gz exists 
     ok 5 - Decompress gzip1.htm.gz with gzip of opportunity; Validate gzip1.htm 
     ok 6 - Compress gzip1.htm with site os GNU gzip. Validate gzip1.htm.gz exists 
     ok 7 - Decompress with site os GNU gzip. Validate gzip1.htm 
     ok 8 - Compress gzip1.htm with Compress::Zlib. Valid gzip1.htm.gz exists. 
     ok 9 - Decompress gzip1.htm.gz with site OS GNU gzip. Validate gzip1.htm 
     ok 10 - Compress gzip1.htm with site os GNU gzip. Validate gzip1.htm.gz exists. 
     ok 11 - Decompress gzip1.htm.gz with Compress::Zlib. Validate gzip1.htm. 
     # Passed : 11/11 100%

  Test Script Software and Operation

    Running the test script 'Gzip.t' found in the "Tie-Gzip-$VERSION.tar.gz"
    distribution file verifies the requirements for this module.

    All testing software and documentation stems from the Software Test
    Description (STD) program module 't::Tie::Gzip', found in the
    distribution file "Tie-Gzip-$VERSION.tar.gz".

    The 't::Tie::Gzip' STD POD contains a tracebility matix between the
    requirements established above for this module, and the test steps
    identified by a 'ok' number from running the 'Gzip.t' test script.

    The t::Tie::Gzip' STD program module '__DATA__' section contains the
    data to perform the following:

    *   to generate the test script 'Gzip.t'

    *   generate the tailored STD POD in the 't::Tie::Gzip' module,

    *   generate the 'Gzip.d' demo script,

    *   replace the POD demonstration section herein with the demo script
        'Gzip.d' output, and

    *   run the test script using Test::Harness with or without the verbose
        option,

    To perform all the above, prepare and run the automation software as
    follows:

    *   Install "Test_STDmaker-$VERSION.tar.gz" from one of the
        respositories only if it has not been installed:

        *   http://www.softwarediamonds/packages/

        *   http://www.perl.com/CPAN-local/authors/id/S/SO/SOFTDIA/

    *   manually place the script tmake.pl in
        "Test_STDmaker-$VERSION.tar.gz' in the site operating system
        executable path only if it is not in the executable path

    *   place the 't::Tie::Gzip' at the same level in the directory struture
        as the directory holding the 'Tie::Gzip' module

    *   execute the following in any directory:

         tmake -test_verbose -replace -run -pm=t::Tie::Gzip

NOTES
  RELATED MODULES

    The package 'CPAN::Tarzip::TIEHANDLE' buried deep in the 'CPAN' module
    has a bare bones tie to decompress gzip files. A study of this package
    proved valuable in identifying some of the pitfalls that the author of
    this package encountered in his similar endeavor. One issue was that
    'Compress::Zlib' gzip subroutines/methods will return data entact from a
    file that is not compress as well as compress gzip file contents without
    any signaling of the differences in the raw file contents.

    This 'Compress::Gzip' module follows the overall direction of
    'CPAN::Tarzip::TIEHANDLE' in handling this issue with a different code
    implementation.

    Another related module is the 'PerlIO::gzip' module that implements the
    gzip file disciplines. Gzip file disciplines are available in the newer
    version of Perls. Altough the C code was not examined for this module,
    there appears in the POD a somewhat different approach to processing the
    file content that is not gzip compressed. There is a lot of gzip header
    checking and whatever.

    Many of the older Perls in wide spread use do not support file
    disciplines.

    head2 FEEDBACK

    From: Mark.Scarton@FranklinCovey.com Date: Thu, 19 Feb 2004 17:23:37
    -0700

    In the 'lib/Tie/Gzip.pm' module of the Tie-Gzip-0.01 package, the open
    of the pipe ("gzip --decompress --stdout |") is failing due to the
    reference to $! in the conditional. As a test, I cleared $! before
    issuing the open call as follows:

    Line 124:

                 ###############
                 # Some perls will return a glob and a warning
                 # for certain pipe errors such as the command
                 # not a recognized command
                 #
                 $! = 0;    ### MAS ###
                 my $success = open PIPE, $pipe;
                 if($! || !$success) {
                     warn "Could not pipe $pipe: $!\n";
                     $self->CLOSE;
                     return undef;
                 }

    Line 167:

                 ###############
                 # Some perls will return a glob and a warning
                 # for certain pipe errors such as the command
                 # not a recognized command
                 #
                 $! = 0;    ### MAS ###
                 my $success = open PIPE, $pipe;
                 if($! || !$success) {
                     warn "Could not pipe $pipe: $!\n";
                     $self->CLOSE;
                     return undef;
                 }

    This works. Prior to making this change, test 6 of Gzip.t would fail.

    According to the Learning Perl O'Reilly book,

    "But if you use die to indicate an error that is not the failure of a
    system request, don't include $!, since it will generally hold an
    unrelated message left over from something Perl did internally. It will
    hold a useful value only immediately after a failed system request. A
    successful request won't leave anything useful there."

    So $! is only sourced when a system error occurs and it is not cleared
    prior to the call. If no error occurs, the value is indeterminate.

    head2 FILES

    The installation of the "Tie-Gzip-$VERSION.tar.gz" distribution file
    installs the 'Docs::Site_SVD::Tie_Gzip' SVD program module.

    The __DATA__ data section of the 'Docs::Site_SVD::Tie_Gzip' contains all
    the necessary data to generate the POD section of
    'Docs::Site_SVD::Tie_Gzip' and the "Tie-Gzip-$VERSION.tar.gz"
    distribution file.

    To make use of the 'Docs::Site_SVD::Tie_Gzip' SVD program module,
    perform the following:

    *   install "ExtUtils-SVDmaker-$VERSION.tar.gz" from one of the
        respositories only if it has not been installed:

        *   http://www.softwarediamonds/packages/

        *   http://www.perl.com/CPAN-local/authors/id/S/SO/SOFTDIA/

    *   manually place the script vmake.pl in
        "ExtUtils-SVDmaker-$VERSION.tar.gz' in the site operating system
        executable path only if it is not in the executable path

    *   Make any appropriate changes to the __DATA__ section of the
        'Docs::Site_SVD::Tie_Gzip' module. For example, any changes to
        'Tie::Gzip' will impact the at least 'Changes' field.

    *   Execute the following:

         vmake readme_html all -pm=Docs::Site_SVD::Tie_Gzip -verbose

  AUTHOR

    The holder of the copyright and maintainer is

    <support@SoftwareDiamonds.com>

  COPYRIGHT NOTICE

    Copyrighted (c) 2002 Software Diamonds

    All Rights Reserved

  BINDING REQUIREMENTS NOTICE

    Binding requirements are indexed with the pharse 'shall[dd]' where dd is
    an unique number for each header section. This conforms to standard
    federal government practices, 490A (the 3.2.3.6 entry in the STD490A
    manpage). In accordance with the License for 'Tie::Gzip', Software
    Diamonds is not liable for meeting any requirement, binding or
    otherwise.

  LICENSE

    Software Diamonds permits the redistribution and use in source and
    binary forms, with or without modification, provided that the following
    conditions are met:

    1   Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

    2   Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

    SOFTWARE DIAMONDS, http::www.softwarediamonds.com, PROVIDES THIS
    SOFTWARE 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
    NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SOFTWARE
    DIAMONDS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL,EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF NEGLIGENCE OR OTHERWISE) ARISING IN
    ANY WAY OUT OF THE POSSIBILITY OF SUCH DAMAGE.

SEE ALSO
    the CSPAN manpage, the PerlIO::gzip manpage, the Test::STDmaker manpage,
    the Docs::US_DOD::STD manpage, the ExtUtils::SVDmaker manpage, the
    Docs::US_DOD::SVD manpage, the gzip manpage, rfc 1952 (the gzip file
    format specification), rfc 1951 (DEFLATE compressed data format
    specification)

Title Page
     Software Version Description

     for

     Tie::Gzip - gzip with a small memory footprint

     Revision: B

     Version: 0.04

     Date: 2004/04/15

     Prepared for: General Public 

     Prepared by:  SoftwareDiamonds.com E<lt>support@SoftwareDiamonds.comE<gt>

     Copyright: copyright © 2003 Software Diamonds

     Classification: NONE

1.0 SCOPE
    This paragraph identifies and provides an overview of the released
    files.

  1.1 Identification

    This release, identified in 3.2, is a collection of Perl modules that
    extend the capabilities of the Perl language.

  1.2 System overview

    The 'Tie::Gzip' module provides a file handle Tie for compressing and
    uncompressing files using the gzip format.

    By tieing a filehandle to 'Tie::Gzip' subsequent uses of the file
    subroutines with the tied filehandle will compress data written to an
    opened file using gzip compression and decompress data read from an
    opened file using gzip compression.

    If the 'Tie::Gzip' tie receives a *filename* or *mode filename* after
    completing the tie, 'Tie::Gzip' will open *filename*.

    During the tie, Tie::Gzip will first try to load the 'Compress::Zlib'
    module and package. If successful, 'Tie::Gzip' uses the 'Compress::Zlib'
    for compressing and decompressing the file data.

    If unsuccessful, 'Tie::Gzip' setups up the following pipes to an
    anticipated GNU 'gzip' site command for compressing and decompressing
    the file data:

     gzip --decompress --stdout {} | # read file data
     | gzip --stdout > {} # write file data

    where the string '{}' is a placeholder for the *filename*.

  1.3 Document overview.

    This document releases Tie::Gzip version 0.04 providing a description of
    the inventory, installation instructions and other information necessary
    to utilize and track this release.

3.0 VERSION DESCRIPTION
    All file specifications in this SVD use the Unix operating system file
    specification.

  3.1 Inventory of materials released.

    This document releases the file

     Tie-Gzip-0.04.tar.gz

    found at the following repository(s):

      http://www.softwarediamonds/packages/
      http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/

    Restrictions regarding duplication and license provisions are as
    follows:

    Copyright.
        copyright © 2003 Software Diamonds

    Copyright holder contact.
         603 882-0846 E<lt>support@SoftwareDiamonds.comE<gt>

    License.
        Software Diamonds permits the redistribution and use in source and
        binary forms, with or without modification, provided that the
        following conditions are met:

        1   Redistributions of source code, modified or unmodified must
            retain the above copyright notice, this list of conditions and
            the following disclaimer.

        2   Redistributions in binary form must reproduce the above
            copyright notice, this list of conditions and the following
            disclaimer in the documentation and/or other materials provided
            with the distribution.

        SOFTWARE DIAMONDS, http://www.SoftwareDiamonds.com, PROVIDES THIS
        SOFTWARE 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
        BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
        FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
        SOFTWARE DIAMONDS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
        SPECIAL,EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
        LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
        USE,DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
        ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
        OR TORT (INCLUDING USE OF THIS SOFTWARE, EVEN IF ADVISED OF
        NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE POSSIBILITY
        OF SUCH DAMAGE.

  3.2 Inventory of software contents

    The content of the released, compressed, archieve file, consists of the
    following files:

     file                                                         version date       comment
     ------------------------------------------------------------ ------- ---------- ------------------------
     lib/Docs/Site_SVD/Tie_Gzip.pm                                0.04    2004/04/15 revised 0.03
     MANIFEST                                                     0.04    2004/04/15 generated, replaces 0.03
     Makefile.PL                                                  0.04    2004/04/15 generated, replaces 0.03
     README                                                       0.04    2004/04/15 generated, replaces 0.03
     lib/Tie/Gzip.pm                                              1.13    2004/04/15 revised 1.12
     t/Tie/Gzip.pm                                                0.03    2004/04/15 revised 0.02
     t/Tie/Gzip.t                                                 0.02    2004/04/15 revised 0.01
     t/Tie/Gzip.d                                                 0.02    2004/04/15 revised 0.01
     t/Tie/File/Package.pm                                        1.16    2004/04/15 new
     t/Tie/File/SmartNL.pm                                        1.13    2004/04/15 new
     t/Tie/Test/Tech.pm                                           1.18    2004/04/15 new
     t/Tie/Data/Secs2.pm                                          1.16    2004/04/15 new
     t/Tie/Data/SecsPack.pm                                       0.02    2004/04/15 new
     t/Tie/Gzip0.htm                                              0.01    2003/09/12 unchanged

  3.3 Changes

    Changes are as follows

    Tie::Gzip-0.01
        Originated

    Tie::Gzip-0.02
        Installed Mark Scarton's engineering change request per below
        e-mail:

        From: Mark.Scarton@FranklinCovey.com Date: Thu, 19 Feb 2004 17:23:37
        -0700

        In the 'lib/Tie/Gzip.pm' module of the Tie-Gzip-0.01 package, the
        open of the pipe ("gzip --decompress --stdout |") is failing due to
        the reference to $! in the conditional. As a test, I cleared $!
        before issuing the open call as follows:

         Line 124:

                     ###############
                     # Some perls will return a glob and a warning
                     # for certain pipe errors such as the command
                     # not a recognized command
                     #
                     $! = 0;    ### MAS ###
                     my $success = open PIPE, $pipe;
                     if($! || !$success) {
                         warn "Could not pipe $pipe: $!\n";
                         $self->CLOSE;
                         return undef;
                     }

         Line 167:

                     ###############
                     # Some perls will return a glob and a warning
                     # for certain pipe errors such as the command
                     # not a recognized command
                     #
                     $! = 0;    ### MAS ###
                     my $success = open PIPE, $pipe;
                     if($! || !$success) {
                         warn "Could not pipe $pipe: $!\n";
                         $self->CLOSE;
                         return undef;
                     }

        This works. Prior to making this change, test 6 of Gzip.t would
        fail.

        According to the Learning Perl O'Reilly book,

        "But if you use die to indicate an error that is not the failure of
        a system request, don't include $!, since it will generally hold an
        unrelated message left over from something Perl did internally. It
        will hold a useful value only immediately after a failed system
        request. A successful request won't leave anything useful there."

        So $! is only sourced when a system error occurs and it is not
        cleared prior to the call. If no error occurs, the value is
        indeterminate.

    Tie::Gzip-0.03
        prerequisite program because loaded the Data::Secs2 test modules to
        tlib\Test instead of tlib\Data.

    Tie::Gzip-0.04
        The lastest build of Test::STDmaker expects the test library in the
        same directory as the test script. Coordiated with the lastest
        Test::STDmaker by moving the test library from tlib to t/Tie, the
        same directory as the test script and deleting the test library
        File::TestPath program module.

        http://ppm.activestate.com/BuildStatus/5.8-linux/linux-5.8/Tie-Gzip-
        0.03.txt

        has the following failures:

         PERL_DL_NONLAZY=1 /home/cpanrun/tmp/5.8.0/bin/perl "-MExtUtils::Command::MM" "-e" "test_harness(0, 'blib/lib', 'blib/arch')" t/Tie/Gzip.t
         t/Tie/Gzip....Could not pipe | gzip --stdout > Gzip1.htm.gz: Illegal seek
         Could not pipe gzip --decompress --stdout Gzip1.htm.gz |: Illegal seek
         Could not pipe gzip --decompress --stdout Gzip1.htm.gz |: Illegal seek
         # Cannot open <Gzip1.htm
         # Test 9 got: '' (t/Tie/Gzip.t at line 319)
         #   Expected: '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
         <html>

         [snip]

         FAILED test 9
                Failed 1/11 tests, 90.91% okay (less 5 skipped tests: 5 okay, 45.45%)
         Failed 1/1 test scripts, 0.00% okay. 1/11 subtests failed, 90.91% okay.
         Failed Test  Stat Wstat Total Fail  Failed  List of Failed
         -------------------------------------------------------------------------------
         t/Tie/Gzip.t               11    1   9.09%  9
         5 subtests skipped.

        The test script is not right and this is a false failure. The test
        script uses the <Test:Tech> features to force the "ok" and "skip" to
        perform a skip. However, this does not work for Perl code outside
        the "ok" and "skip" subroutines. Added test code to skip outside the
        "ok" and "skip" subroutines.

  3.4 Adaptation data.

    This installation requires that the installation site has the Perl
    programming language installed. There are no other additional
    requirements or tailoring needed of configurations files, adaptation
    data or other software needed for this installation particular to any
    installation site.

  3.5 Related documents.

    There are no related documents needed for the installation and test of
    this release.

  3.6 Installation instructions.

    Instructions for installation, installation tests and installation
    support are as follows:

    Installation Instructions.
        To installed the release file, use the CPAN module pr PPM module in
        the Perl release or the INSTALL.PL script at the following web site:

         http://packages.SoftwareDiamonds.com

        Follow the instructions for the the chosen installation software.

        If all else fails, the file may be manually installed. Enter one of
        the following repositories in a web browser:

          http://www.softwarediamonds/packages/
          http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/

        Right click on 'Tie-Gzip-0.04.tar.gz' and download to a temporary
        installation directory. Enter the following where $make is 'nmake'
        for microsoft windows; otherwise 'make'.

         gunzip Tie-Gzip-0.04.tar.gz
         tar -xf Tie-Gzip-0.04.tar
         perl Makefile.PL
         $make test
         $make install

        On Microsoft operating system, nmake, tar, and gunzip must be in the
        exeuction path. If tar and gunzip are not install, download and
        install unxutils from

         http://packages.softwarediamonds.com

    Prerequistes.
         None.

    Security, privacy, or safety precautions.
        None.

    Installation Tests.
        Most Perl installation software will run the following test
        script(s) as part of the installation:

         t/Tie/Gzip.t

    Installation support.
        If there are installation problems or questions with the
        installation contact

         603 882-0846 E<lt>support@SoftwareDiamonds.comE<gt>

  3.7 Possible problems and known errors

    There are no known open issues.

4.0 NOTES
    The following are useful acronyms:

    .d  extension for a Perl demo script file

    .pm extension for a Perl Library Module

    .t  extension for a Perl test script file

2.0 SEE ALSO
    Docs::US_DOD::SVD
          http://www.softwarediamonds/packages/  Docs-US_DOD-STD2167A-X.XX.tar.gz
          http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/  Docs-US_DOD-STD2167A-X.XX.tar.gz

