Re^2: Readonly problems ( Scalar::Readonly::readonly )

?node_id=3989;HIT=readonly;re=N: Just what is 'readonly' in Perl and Perl 6?; Readonly variable; Module Readonly; What is the difference between the constant construct in Perl and the Readonly construct in Perl?; Reliability of SvREADONLY

Faster way to readonly are Attribute::Constant, Data::Lock, Scalar::Readonly,

use Scalar::Readonly qw/ readonly_on /;
use Devel::Peek qw/ Dump /;
my $f=66;
readonly_on($f);
Dump($f);
__END__
SV = IV(0x99ba38) at 0x99ba3c
  REFCNT = 1
  FLAGS = (PADMY,IOK,READONLY,pIOK)
  IV = 66
[download]

Scalar::Readonly::readonly also simply checks for SvREADONLY flag, and no others (no FAKE), so it'll be a false positive on HASH keys

Comment on Re^2: Readonly problems ( Scalar::Readonly::readonly ) Download Code

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Re^3: Readonly problems ( Scalar::Readonly::readonly ) by runrig (Abbot) on Dec 17, 2013 at 01:47 UTC
Thanks, I don't really want to use readonly() though, I was just tracking down a bug involving DBI/DBD::Oracle. I tracked it down to code that went something like: `my $data = {}; my $sth = $dbh->prepare($sql); $sth->bind_param_inout(':foo' => \$data->{foo}, 10); while ( my ($k, $v) = each %hash ) { $data->{foo} = $k; $sth->execute(); }` [download] And I got a 'modification of readonly value' error on the execute. Workaround is to modify the 'readonly' value before the execute with something like: `$k .= '';` [download] Update: And for now, that whole thing needs a reset every few iterations, as execute() leaks memory with inout parameters. Update2: And the previously mentioned 'leak' has been fixed in the latest release.	[reply] [d/l] [select]
Re^4: Readonly problems ( Scalar::Readonly::readonly ) by choroba (Cardinal) on Dec 17, 2013 at 14:53 UTC
Would the following also work? `$data->{foo} = "$k";` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^5: Readonly problems ( Scalar::Readonly::readonly ) by runrig (Abbot) on Dec 17, 2013 at 16:47 UTC
`$data->{foo} = "$k";` [download] Yes, thanks, that does work. And is one of the few otherwise "useless use of quotes" that is not actually "useless" :-)	[reply] [d/l]
Re^6: Readonly problems ( Scalar::Readonly::readonly ) by choroba (Cardinal) on Dec 17, 2013 at 17:08 UTC