[26397] in Perl-Users-Digest
Perl-Users Digest, Issue: 8568 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Oct 25 18:05:30 2005
Date: Tue, 25 Oct 2005 15:05:06 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Tue, 25 Oct 2005 Volume: 10 Number: 8568
Today's topics:
Re: Access a c++ module from Perl <"harryfmudd [AT] comcast [DOT] net">
FAQ 7.16 What's the difference between dynamic and lexi <comdog@pair.com>
Re: varhash question (Jeremy Billones)
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
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Date: Tue, 25 Oct 2005 14:51:59 -0400
From: "harryfmudd [AT] comcast [DOT] net" <"harryfmudd [AT] comcast [DOT] net">
Subject: Re: Access a c++ module from Perl
Message-Id: <2qGdncmm-bpN48PeRVn-hg@comcast.com>
bg-greece wrote:
> the dll was created with with Microsoft Visual C++ 6.0
Are you using the Cygwin distribution of Perl? I think you will find
that it was _not_ made with Visual C++ V6, but with gcc.
I personally have had good luck with Win32::API, though sometimes it was
not obvious how to describe the function I wanted to import, and when
you get the description wrong, you do get segment violations. I do not
remember using the new, sexy prototype interface, just the old, clunky
one. See Win32::Process::Info::NT for an example.
Disclaimer: I wrote the cited module. And I never said it was a _good_
example.
Tom Wyant
------------------------------
Date: Tue, 25 Oct 2005 22:03:01 +0000 (UTC)
From: PerlFAQ Server <comdog@pair.com>
Subject: FAQ 7.16 What's the difference between dynamic and lexical (static) scoping? Between local() and my()?
Message-Id: <djma2l$6r7$1@reader2.panix.com>
This message is one of several periodic postings to comp.lang.perl.misc
intended to make it easier for perl programmers to find answers to
common questions. The core of this message represents an excerpt
from the documentation provided with Perl.
--------------------------------------------------------------------
7.16: What's the difference between dynamic and lexical (static) scoping? Between local() and my()?
"local($x)" saves away the old value of the global variable $x and
assigns a new value for the duration of the subroutine *which is visible
in other functions called from that subroutine*. This is done at
run-time, so is called dynamic scoping. local() always affects global
variables, also called package variables or dynamic variables.
"my($x)" creates a new variable that is only visible in the current
subroutine. This is done at compile-time, so it is called lexical or
static scoping. my() always affects private variables, also called
lexical variables or (improperly) static(ly scoped) variables.
For instance:
sub visible {
print "var has value $var\n";
}
sub dynamic {
local $var = 'local'; # new temporary value for the still-global
visible(); # variable called $var
}
sub lexical {
my $var = 'private'; # new private variable, $var
visible(); # (invisible outside of sub scope)
}
$var = 'global';
visible(); # prints global
dynamic(); # prints local
lexical(); # prints global
Notice how at no point does the value "private" get printed. That's
because $var only has that value within the block of the lexical()
function, and it is hidden from called subroutine.
In summary, local() doesn't make what you think of as private, local
variables. It gives a global variable a temporary value. my() is what
you're looking for if you want private variables.
See "Private Variables via my()" in perlsub and "Temporary Values via
local()" in perlsub for excruciating details.
--------------------------------------------------------------------
Documents such as this have been called "Answers to Frequently
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The perlfaq manual page contains the following copyright notice.
AUTHOR AND COPYRIGHT
Copyright (c) 1997-2002 Tom Christiansen and Nathan
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This posting is provided in the hope that it will be useful but
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------------------------------
Date: Tue, 25 Oct 2005 18:57:06 -0000
From: billones@radix.net (Jeremy Billones)
Subject: Re: varhash question
Message-Id: <11lt0022j6458f8@corp.supernews.com>
I've discovered that a major portion of the problem is a conflict within
Cygwin as to how it accesses files and filenames, which is propogated
all the way through the application (which assumes a UNIX file layout
and which cygwin doesn't quite support completely).
*Those* scripts I think I can edit.
Again, thanks all for putting up with (yet another) Perl newbie.
--
Jeremy Billones
"It's a place used the world over where people can come together to bitch about
movies and share pornography together." This is a much more sophisticated idea
of the Net than we find in high-tech cyberthrillers, where the Net is a place
that makes your computer beep a lot. - Roger Ebert on "Jay & Silent Bob..."
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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End of Perl-Users Digest V10 Issue 8568
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