NDBM_File 5.8.8

NDBM_File is a Perl module that allows tied access to ndbm files.

SYNOPSIS

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

tie(%h, NDBM_File, filename, O_RDWR|O_CREAT, 0666)
or die "Couldnt tie NDBM file filename: $!; aborting";

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

untie %h;

NDBM_File establishes a connection between a Perl hash variable and a file in NDBM_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 NDBM_File with the Perl built-in tie function to establish the connection between the variable and the file. The arguments to tie should be:

The hash variable you want to tie.

The string "NDBM_File". (Ths tells Perl to use the NDBM_File package to perform the functions of the hash.)

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

Flags. Use one of:

O_RDONLY

Read-only access to the data in the file.

O_WRONLY

Write-only access to the data in the file.

O_RDWR

Both read and write access.

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

The default permissions to use if a new file is created. The actual permissions will be modified by the users umask, so you should probably use 0666 here. (See "umask" in perlfunc.)