ext/ODBM_File/ODBM_File.pm

package ODBM_File;

use strict;
use warnings;

require Tie::Hash;
use XSLoader ();

our @ISA = qw(Tie::Hash);
our $VERSION = "1.05";

XSLoader::load 'ODBM_File', $VERSION;

1;

__END__

=head1 NAME

ODBM_File - Tied access to odbm files

=head1 SYNOPSIS

 use Fcntl;   # For O_RDWR, O_CREAT, etc.
 use ODBM_File;

  # Now read and change the hash
  $h{newkey} = newvalue;
  print $h{oldkey}; 
  ...

  untie %h;

=head1 DESCRIPTION

C<ODBM_File> establishes a connection between a Perl hash variable and
a file in ODBM_File format;.  You can manipulate the data in the file
just as if it were in a Perl hash, but when your program exits, the
data will remain in the file, to be used the next time your program
runs.

Use C<ODBM_File> with the Perl built-in C<tie> function to establish
the connection between the variable and the file.  The arguments to
C<tie> should be:

=over 4

=item 1.

The hash variable you want to tie.

=item 2. 

The string C<"ODBM_File">.  (Ths tells Perl to use the C<ODBM_File>
package to perform the functions of the hash.)

=item 3. 

The name of the file you want to tie to the hash.  

=item 4.

Flags.  Use one of:

=over 2

=item C<O_RDONLY>

Read-only access to the data in the file.

=item C<O_WRONLY>

Write-only access to the data in the file.

=item C<O_RDWR>

Both read and write access.

=back

If you want to create the file if it does not exist, add C<O_CREAT> to
any of these, as in the example.  If you omit C<O_CREAT> and the file
does not already exist, the C<tie> call will fail.

=item 5.

The default permissions to use if a new file is created.  The actual
permissions will be modified by the user's umask, so you should
probably use 0666 here. (See L<perlfunc/umask>.)

=back

=head1 DIAGNOSTICS

On failure, the C<tie> call returns an undefined value and probably
sets C<$!> to contain the reason the file could not be tied.

=head2 C<odbm store returned -1, errno 22, key "..." at ...>

This warning is emmitted when you try to store a key or a value that
is too long.  It means that the change was not recorded in the
database.  See BUGS AND WARNINGS below.

=head1 BUGS AND WARNINGS

There are a number of limits on the size of the data that you can
store in the ODBM file.  The most important is that the length of a
key, plus the length of its associated value, may not exceed 1008
bytes.

See L<perlfunc/tie>, L<perldbmfilter>, L<Fcntl>

=cut
Revision:	1.1
Committed:	Thu Jun 30 14:27:03 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	package ODBM_File;
2
3			use strict;
4			use warnings;
5
6			require Tie::Hash;
7			use XSLoader ();
8
9			our @ISA = qw(Tie::Hash);
10			our $VERSION = "1.05";
11
12			XSLoader::load 'ODBM_File', $VERSION;
13
14			1;
15
16			__END__
17
18			=head1 NAME
19
20			ODBM_File - Tied access to odbm files
21
22			=head1 SYNOPSIS
23
24			use Fcntl; # For O_RDWR, O_CREAT, etc.
25			use ODBM_File;
26
27			# Now read and change the hash
28			$h{newkey} = newvalue;
29			print $h{oldkey};
30			...
31
32			untie %h;
33
34			=head1 DESCRIPTION
35
36			C<ODBM_File> establishes a connection between a Perl hash variable and
37			a file in ODBM_File format;. You can manipulate the data in the file
38			just as if it were in a Perl hash, but when your program exits, the
39			data will remain in the file, to be used the next time your program
40			runs.
41
42			Use C<ODBM_File> with the Perl built-in C<tie> function to establish
43			the connection between the variable and the file. The arguments to
44			C<tie> should be:
45
46			=over 4
47
48			=item 1.
49
50			The hash variable you want to tie.
51
52			=item 2.
53
54			The string C<"ODBM_File">. (Ths tells Perl to use the C<ODBM_File>
55			package to perform the functions of the hash.)
56
57			=item 3.
58
59			The name of the file you want to tie to the hash.
60
61			=item 4.
62
63			Flags. Use one of:
64
65			=over 2
66
67			=item C<O_RDONLY>
68
69			Read-only access to the data in the file.
70
71			=item C<O_WRONLY>
72
73			Write-only access to the data in the file.
74
75			=item C<O_RDWR>
76
77			Both read and write access.
78
79			=back
80
81			If you want to create the file if it does not exist, add C<O_CREAT> to
82			any of these, as in the example. If you omit C<O_CREAT> and the file
83			does not already exist, the C<tie> call will fail.
84
85			=item 5.
86
87			The default permissions to use if a new file is created. The actual
88			permissions will be modified by the user's umask, so you should
89			probably use 0666 here. (See L<perlfunc/umask>.)
90
91			=back
92
93			=head1 DIAGNOSTICS
94
95			On failure, the C<tie> call returns an undefined value and probably
96			sets C<$!> to contain the reason the file could not be tied.
97
98			=head2 C<odbm store returned -1, errno 22, key "..." at ...>
99
100			This warning is emmitted when you try to store a key or a value that
101			is too long. It means that the change was not recorded in the
102			database. See BUGS AND WARNINGS below.
103
104			=head1 BUGS AND WARNINGS
105
106			There are a number of limits on the size of the data that you can
107			store in the ODBM file. The most important is that the length of a
108			key, plus the length of its associated value, may not exceed 1008
109			bytes.
110
111			See L<perlfunc/tie>, L<perldbmfilter>, L<Fcntl>
112
113			=cut