File | /usr/lib/perl/5.10/SDBM_File.pm |
Statements Executed | 14 |
Total Time | 0.0004317 seconds |
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0 | 0 | 0 | 0s | 0s | BEGIN | SDBM_File::
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1 | package SDBM_File; | |||
2 | ||||
3 | 3 | 35µs | 12µs | use strict; # spent 13µs making 1 call to strict::import |
4 | 3 | 33µs | 11µs | use warnings; # spent 25µs making 1 call to warnings::import |
5 | ||||
6 | 1 | 700ns | 700ns | require Tie::Hash; |
7 | 3 | 67µs | 22µs | use XSLoader (); |
8 | ||||
9 | 1 | 8µs | 8µs | our @ISA = qw(Tie::Hash); |
10 | 1 | 500ns | 500ns | our $VERSION = "1.06"; |
11 | ||||
12 | 1 | 275µs | 275µs | XSLoader::load 'SDBM_File', $VERSION; # spent 274µs making 1 call to XSLoader::load |
13 | ||||
14 | 1 | 12µs | 12µs | 1; |
15 | ||||
16 | __END__ | |||
17 | ||||
18 | =head1 NAME | |||
19 | ||||
20 | SDBM_File - Tied access to sdbm files | |||
21 | ||||
22 | =head1 SYNOPSIS | |||
23 | ||||
24 | use Fcntl; # For O_RDWR, O_CREAT, etc. | |||
25 | use SDBM_File; | |||
26 | ||||
27 | tie(%h, 'SDBM_File', 'filename', O_RDWR|O_CREAT, 0666) | |||
28 | or die "Couldn't tie SDBM file 'filename': $!; aborting"; | |||
29 | ||||
30 | # Now read and change the hash | |||
31 | $h{newkey} = newvalue; | |||
32 | print $h{oldkey}; | |||
33 | ... | |||
34 | ||||
35 | untie %h; | |||
36 | ||||
37 | =head1 DESCRIPTION | |||
38 | ||||
39 | C<SDBM_File> establishes a connection between a Perl hash variable and | |||
40 | a file in SDBM_File format;. You can manipulate the data in the file | |||
41 | just as if it were in a Perl hash, but when your program exits, the | |||
42 | data will remain in the file, to be used the next time your program | |||
43 | runs. | |||
44 | ||||
45 | Use C<SDBM_File> with the Perl built-in C<tie> function to establish | |||
46 | the connection between the variable and the file. The arguments to | |||
47 | C<tie> should be: | |||
48 | ||||
49 | =over 4 | |||
50 | ||||
51 | =item 1. | |||
52 | ||||
53 | The hash variable you want to tie. | |||
54 | ||||
55 | =item 2. | |||
56 | ||||
57 | The string C<"SDBM_File">. (Ths tells Perl to use the C<SDBM_File> | |||
58 | package to perform the functions of the hash.) | |||
59 | ||||
60 | =item 3. | |||
61 | ||||
62 | The name of the file you want to tie to the hash. | |||
63 | ||||
64 | =item 4. | |||
65 | ||||
66 | Flags. Use one of: | |||
67 | ||||
68 | =over 2 | |||
69 | ||||
70 | =item C<O_RDONLY> | |||
71 | ||||
72 | Read-only access to the data in the file. | |||
73 | ||||
74 | =item C<O_WRONLY> | |||
75 | ||||
76 | Write-only access to the data in the file. | |||
77 | ||||
78 | =item C<O_RDWR> | |||
79 | ||||
80 | Both read and write access. | |||
81 | ||||
82 | =back | |||
83 | ||||
84 | If you want to create the file if it does not exist, add C<O_CREAT> to | |||
85 | any of these, as in the example. If you omit C<O_CREAT> and the file | |||
86 | does not already exist, the C<tie> call will fail. | |||
87 | ||||
88 | =item 5. | |||
89 | ||||
90 | The default permissions to use if a new file is created. The actual | |||
91 | permissions will be modified by the user's umask, so you should | |||
92 | probably use 0666 here. (See L<perlfunc/umask>.) | |||
93 | ||||
94 | =back | |||
95 | ||||
96 | =head1 DIAGNOSTICS | |||
97 | ||||
98 | On failure, the C<tie> call returns an undefined value and probably | |||
99 | sets C<$!> to contain the reason the file could not be tied. | |||
100 | ||||
101 | =head2 C<sdbm store returned -1, errno 22, key "..." at ...> | |||
102 | ||||
103 | This warning is emitted when you try to store a key or a value that | |||
104 | is too long. It means that the change was not recorded in the | |||
105 | database. See BUGS AND WARNINGS below. | |||
106 | ||||
107 | =head1 BUGS AND WARNINGS | |||
108 | ||||
109 | There are a number of limits on the size of the data that you can | |||
110 | store in the SDBM file. The most important is that the length of a | |||
111 | key, plus the length of its associated value, may not exceed 1008 | |||
112 | bytes. | |||
113 | ||||
114 | See L<perlfunc/tie>, L<perldbmfilter>, L<Fcntl> | |||
115 | ||||
116 | =cut |