TieRegistry FastDelete problem

anadem has asked for the wisdom of the Perl Monks concerning the following question:

I'd like to have delete operations on the registry return true/false. The docs for TieRegistry (at tinyurl.com/5ofltk) say

".. by calling the FastDelete member function:
#
#    $prevSetting= $regKey->FastDelete(1);
#
# which will cause all subsequent delete operations via $regKey to sim
+ply return a true value if they succeed.
[download]

Unfortunately I'm too dumb to get it to work. In my code, when deleting a reg value (not key) the delete operation either deletes the value and returns its data, or, when the value is not in the registry the delete fails and returns a string "The system cannot find the file specified."

Can some kind monk please point out the error of my ways?
Here's a simple sample:

use Win32::TieRegistry( Delimiter=>"/", ArrayValues=>1 );

$key = "LMachine/Software/Microsoft/Windows/CurrentVersion/SharedDlls/
+";
$value = "c:\\aaa.aaa";

# $Registry->{ $key } = { "/$value" => [ "0x0003", "REG_DWORD" ] };

$prevSetting = $Registry->FastDelete(1);

$res = delete $Registry->{ $key . $value };
if( $res )
{
    print( "removed value $value and res is $res\n" );
}
else
{
    print( " delete failed and res is '$res'\n" );
}
[download]

Those docs go on to say "This optimization is automatically done if you use delete in a void context."
It may be asking too much, but if someone can tell me in how to use delete in a void context, that would also be helpful.
Many thanks

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Re: TieRegistry FastDelete problem by ikegami (Patriarch) on Jul 10, 2008 at 21:14 UTC
Testing reveals it only applies when deleting keys (as opposed to values). `use strict; use warnings; use Win32::TieRegistry ( Delimiter => '/' ); my $key_path = 'LMachine/Software/DELETE ME/'; $Registry->{$key_path} = {}; $Registry->FastDelete($ARGV[0]); my $res = delete $Registry->{$key_path}; if( $res ) { print( "removed value and res is $res\n" ); } else { print( " delete failed and res is '$res'\n" ); }` [download] `>perl test.pl 0 removed value and res is HASH(0x225374) >perl test.pl 1 removed value and res is 1` [download]	[reply] [d/l] [select]
Re: TieRegistry FastDelete problem by pc88mxer (Vicar) on Jul 10, 2008 at 20:44 UTC
if someone can tell me in how to use delete in a void context, that would also be helpful. Void context means you are not asking for any return values: `delete $Registry->{$key}; # void context $res = delete $Registry->{$key}; # scalar context if (delete $Registry->{$key}) { ... } # also scalar context @results = delete $Registry->{$key}; # list context` [download] Update: 'array' context should be 'list' context (thanks ikegami.)	[reply] [d/l]
Re: TieRegistry FastDelete problem by anadem (Scribe) on Jul 10, 2008 at 22:12 UTC
Thank you, ikegami and pc88mxer. Much appreciated.	[reply]