[31051] in Perl-Users-Digest
Perl-Users Digest, Issue: 2296 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Mar 25 14:09:51 2009
Date: Wed, 25 Mar 2009 11:09:14 -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 Wed, 25 Mar 2009 Volume: 11 Number: 2296
Today's topics:
Re: calculate an average with every data in an array <jogsalot75@yahoo.de>
Re: Debian MySQL Perl DBI - connection terminates unex sln@netherlands.com
How to sleep less then 1 second <tower.grv@gmail.com>
Re: How to sleep less then 1 second (Jens Thoms Toerring)
Re: How to sleep less then 1 second <hjp-usenet2@hjp.at>
Re: How to sleep less then 1 second <jurgenex@hotmail.com>
Re: How to sleep less then 1 second <smallpond@juno.com>
Invoking an SSH client by clicking a URL Link cyrusgreats@gmail.com
PPM error message -- invalid token <cartercc@gmail.com>
Re: PPM error message -- invalid token <smallpond@juno.com>
Re: PPM error message -- invalid token <hjp-usenet2@hjp.at>
RTF to HTML conversion grouchy.oldgit@googlemail.com
Re: RTF to HTML conversion <jkorpela@cs.tut.fi>
Sharing BerkeleyDB among forked children <liarafan@xs4all.nl>
Typeglobs vs References <schaitan@gmail.com>
Re: Typeglobs vs References sln@netherlands.com
Re: Typeglobs vs References <schaitan@gmail.com>
Re: what is the return value type of !1 ? (Tim McDaniel)
Re: what is the return value type of !1 ? <ben@morrow.me.uk>
Re: what is the return value type of !1 ? <tadmc@seesig.invalid>
XML::Reader - request for comments <klaus03@gmail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Wed, 25 Mar 2009 07:19:02 -0700 (PDT)
From: Erol Akman <jogsalot75@yahoo.de>
Subject: Re: calculate an average with every data in an array
Message-Id: <92a1b739-02db-4e12-b1b3-d546d0efca64@c9g2000yqm.googlegroups.com>
Hi Darrin,
thank you very much for your reply and your script. It works very well
and made realize, that my problem is hard to solve.
Thx
-----
Erol
------------------------------
Date: Wed, 25 Mar 2009 08:23:13 GMT
From: sln@netherlands.com
Subject: Re: Debian MySQL Perl DBI - connection terminates unexpectedly after 100 secs.
Message-Id: <48qjs4pvncm15c1p79k32urmvenliido96@4ax.com>
On Wed, 25 Mar 2009 07:01:38 -0000, "John" <john1949@yahoo.com> wrote:
>
>"Jens Thoms Toerring" <jt@toerring.de> wrote in message
>news:727ga0Fo7qv3U1@mid.uni-berlin.de...
>> John <john1949@yahoo.com> wrote:
>>
>>> "J. Gleixner" <glex_no-spam@qwest-spam-no.invalid> wrote in message
>>> news:49be71fd$0$89873$815e3792@news.qwest.net...
>>> > John wrote:
>>> >> I'm updating a MySQL table with about 2 million records. After about
>>> >> 100
>>> >> seconds the program ends with no error message. If I use LIMIT
>>> >> 800000,50000 the part where it stopped is OK so the UPDATE part is OK.
>>> >>
>>> >> Is there a time out parameter? Or am I running out of memory. Can
>>> >> the
>>> >> memory be increased?
>>> >
>>> > Check line 24.
>>
>>> Line 24 says:-
>>
>>> our $old_fh=select(STDOUT); $|=1; select($old_fh); # Make standard output
>>> socket hot
>>
>>> Can't see how that can affect it.
>>
>> I rather guess it was a gentle hint that your problem description
>> is too vague to allow to deduce what's going wrong. But your sub-
>> ject line may contain a hint: it looks as if the update is done
>> from within a CGI script or something similar, running on a web
>> server. And normally there's a CPU time limit set for such scripts
>> to catch e.g. script that run in an endless loop. That's what I
>> would check for first (note: if it's not set then an OS default
>> limit may be used!). If you are using Apache it might be a RLimitCPU
>> directive. But there could also be a limit on the memory consumption
>> of such scripts (RLimitMEM with Apache2)... Perhaps a look at the log
>> files of the web server will give you some more hints.
>>
>> Regards, Jens
>> --
>> \ Jens Thoms Toerring ___ jt@toerring.de
>> \__________________________ http://toerring.de
>
>Many thanks. That was very helpful. I have maxed both RLimitCPU and
>RLimitMEM in Apache2 and that has had led to better performance. There are
>severe problems in using MySQL when you start hitting more than 2 million
>rows irrespective how well you tweak your settings.
>
>Regards
>John
>
>
I am for hire. I've never done your fancy server names stuff.
But I can assure you I am an expert at Data Base and Perl.
The learning curve is like the next day.
Pay me and you get quality software! Price's are negotiable.
I'm looking for full-time at 140K but will work at $120/hr at
minimal time.
-sln
------------------------------
Date: Wed, 25 Mar 2009 07:57:43 -0700 (PDT)
From: "tower.grv@gmail.com" <tower.grv@gmail.com>
Subject: How to sleep less then 1 second
Message-Id: <f3651cf5-1695-4034-8ffd-337f97237900@c9g2000yqm.googlegroups.com>
Hello.
I want my Perl script execute some code in the begining of each
second.
I have code
----------------------------------------------------
#!/usr/bin/perl -w
my $thistime=time();
while(1){
while(time()-$thistime<1) {my $a=1;}
$thistime=time();
print $thistime."\n";
#some more code
}
----------------------------------------------------
This code works but it takes a lot of CPU resources.
sleep(1) is not good for me. Usually it is needed to sleep less then
second.
Is it possible to replace line
while(time()-$thistime<1) {my $a=1;}
with better code?
------------------------------
Date: 25 Mar 2009 15:17:01 GMT
From: jt@toerring.de (Jens Thoms Toerring)
Subject: Re: How to sleep less then 1 second
Message-Id: <72v07dFs8qolU1@mid.uni-berlin.de>
tower.grv@gmail.com <tower.grv@gmail.com> wrote:
> I want my Perl script execute some code in the begining of each
> second.
> I have code
> ----------------------------------------------------
> #!/usr/bin/perl -w
> my $thistime=time();
> while(1){
> while(time()-$thistime<1) {my $a=1;}
> $thistime=time();
> print $thistime."\n";
> #some more code
> }
> ----------------------------------------------------
> This code works but it takes a lot of CPU resources.
> sleep(1) is not good for me. Usually it is needed to sleep less then
> second.
> Is it possible to replace line
> while(time()-$thistime<1) {my $a=1;}
> with better code?
Yes. Use e.g.
select( undef, undef, undef, $delay );
where $delay is the time (in seconds but with sub-second resolution)
you want your process to sleep.
Regards, Jens
--
\ Jens Thoms Toerring ___ jt@toerring.de
\__________________________ http://toerring.de
------------------------------
Date: Wed, 25 Mar 2009 16:25:50 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: How to sleep less then 1 second
Message-Id: <slrngskj7u.gr0.hjp-usenet2@hrunkner.hjp.at>
On 2009-03-25 14:57, tower.grv@gmail.com <tower.grv@gmail.com> wrote:
> This code works but it takes a lot of CPU resources.
> sleep(1) is not good for me. Usually it is needed to sleep less then
> second.
See Time::HiRes
hp
------------------------------
Date: Wed, 25 Mar 2009 09:11:54 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: How to sleep less then 1 second
Message-Id: <uslks4t1upi1n6ui1ub847ftb8vbq9m0u6@4ax.com>
"tower.grv@gmail.com" <tower.grv@gmail.com> wrote:
>sleep(1) is not good for me. Usually it is needed to sleep less then
>second.
You may want to check the FAQ: "perldoc -f second"
How can I sleep() or alarm() for under a second?
jue
------------------------------
Date: Wed, 25 Mar 2009 10:51:57 -0700 (PDT)
From: smallpond <smallpond@juno.com>
Subject: Re: How to sleep less then 1 second
Message-Id: <751ff2dd-e16b-4195-b7be-66fd8af535e8@e24g2000vbe.googlegroups.com>
On Mar 25, 10:57 am, "tower....@gmail.com" <tower....@gmail.com>
wrote:
> Hello.
> I want my Perl script execute some code in the begining of each
> second.
>
> I have code
> ----------------------------------------------------
> #!/usr/bin/perl -w
> my $thistime=time();
> while(1){
>
> while(time()-$thistime<1) {my $a=1;}
>
> $thistime=time();
> print $thistime."\n";
> #some more code
>
> }
>
> ----------------------------------------------------
> This code works but it takes a lot of CPU resources.
> sleep(1) is not good for me. Usually it is needed to sleep less then
> second.
>
> Is it possible to replace line
> while(time()-$thistime<1) {my $a=1;}
> with better code?
TMTOWTDI
Tk has a millisecond timer.
#!/usr/bin/perl
use warnings;
use strict;
use Tk;
my $w = MainWindow->new();
my $times = 10;
sub do_stuff {
print "doing $times\n";
$w->destroy if $times-- == 0;
}
$w->repeat(1000, \&do_stuff);
MainLoop();
------------------------------
Date: Wed, 25 Mar 2009 10:52:22 -0700 (PDT)
From: cyrusgreats@gmail.com
Subject: Invoking an SSH client by clicking a URL Link
Message-Id: <40a1b8a2-4e2f-49a6-a0d6-4729c29e8f53@d19g2000prh.googlegroups.com>
Doe anyone know how to invoke an SSH client by clicking a URL Link.
I'm working on web page and wrote some perl cgi and I need to invoke
an ssh to send command to ssh server or client!
Thanks in advance..
------------------------------
Date: Wed, 25 Mar 2009 08:06:47 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: PPM error message -- invalid token
Message-Id: <539257d3-73cd-4574-bfa3-f4948c4db5ab@p11g2000yqe.googlegroups.com>
Attempting to install GD::Graph with PPM, got the following error
message (copied here in fulll)
<quote>
ppm> install GD::Graph
error: can't parse
<SOFTPKG NAME="autorequire" VERSION="0,08,0,0">
<TITLE>autorequire</TITLE>
<ABSTRACT>Generate module code on demand</ABSTRACT>
<AUTHOR>Patrick LeBoutillier <patl@cpan.org></AUTHOR>
</SO</SOFTPKG>:
not well-formed (invalid token) at line 6, column 6, byte 213 at C:/
Perl/site/lib/XML/Parser.pm line
187
C:\Perl>
</quote>
I looked at Perser.pm and found nothing to fix. What's wrong, and how
can I fix it? If anyone knows.
Thanks, CC.
------------------------------
Date: Wed, 25 Mar 2009 08:41:30 -0700 (PDT)
From: smallpond <smallpond@juno.com>
Subject: Re: PPM error message -- invalid token
Message-Id: <a2e46d3c-6834-4cf8-8e1c-ce0113d7949f@f11g2000vbf.googlegroups.com>
On Mar 25, 11:06 am, ccc31807 <carte...@gmail.com> wrote:
> Attempting to install GD::Graph with PPM, got the following error
> message (copied here in fulll)
>
> <quote>
> ppm> install GD::Graph
> error: can't parse
> <SOFTPKG NAME="autorequire" VERSION="0,08,0,0">
> <TITLE>autorequire</TITLE>
> <ABSTRACT>Generate module code on demand</ABSTRACT>
> <AUTHOR>Patrick LeBoutillier <p...@cpan.org></AUTHOR>
> </SO</SOFTPKG>:
> not well-formed (invalid token) at line 6, column 6, byte 213 at C:/
> Perl/site/lib/XML/Parser.pm line
> 187
>
> C:\Perl>
> </quote>
>
> I looked at Perser.pm and found nothing to fix. What's wrong, and how
> can I fix it? If anyone knows.
>
> Thanks, CC.
Why would Parser.pm have a problem?
It's telling you the exact byte in your ppm file that has a problem.
My guess would be an illegal character. XML can be picky.
------------------------------
Date: Wed, 25 Mar 2009 16:42:33 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: PPM error message -- invalid token
Message-Id: <slrngskk7a.gr0.hjp-usenet2@hrunkner.hjp.at>
On 2009-03-25 15:06, ccc31807 <cartercc@gmail.com> wrote:
><quote>
> ppm> install GD::Graph
> error: can't parse
> <SOFTPKG NAME="autorequire" VERSION="0,08,0,0">
> <TITLE>autorequire</TITLE>
> <ABSTRACT>Generate module code on demand</ABSTRACT>
> <AUTHOR>Patrick LeBoutillier <patl@cpan.org></AUTHOR>
> </SO</SOFTPKG>:
> not well-formed (invalid token) at line 6, column 6, byte 213 at C:/
> Perl/site/lib/XML/Parser.pm line
> 187
>
> C:\Perl>
></quote>
>
> I looked at Perser.pm and found nothing to fix.
If a program complains about the format of a data file, it isn't always
the program which is wrong. In this case it is the data file:
> </SO</SOFTPKG>:
I agree with XML::Parser that this isn't well-formed XML.
hp
------------------------------
Date: Wed, 25 Mar 2009 03:48:38 -0700 (PDT)
From: grouchy.oldgit@googlemail.com
Subject: RTF to HTML conversion
Message-Id: <12805874-268d-4ac7-beae-0f1c6e6384df@o36g2000yqh.googlegroups.com>
Does anyone know of a good, free RTF to (X)HTML conversion utility?
Does not need to convert images / tables etc, just capture <p>,
<strong>, <em>.
------------------------------
Date: Wed, 25 Mar 2009 17:58:08 +0200
From: "Jukka K. Korpela" <jkorpela@cs.tut.fi>
Subject: Re: RTF to HTML conversion
Message-Id: <6xsyl.4185$_f7.2726@uutiset.elisa.fi>
grouchy.oldgit@googlemail.com wrote:
> Does anyone know of a good, free RTF to (X)HTML conversion utility?
> Does not need to convert images / tables etc, just capture <p>,
> <strong>, <em>.
Google for rtf2html.
--
Yucca, http://www.cs.tut.fi/~jkorpela/
------------------------------
Date: Wed, 25 Mar 2009 16:21:54 +0100
From: "Mark" <liarafan@xs4all.nl>
Subject: Sharing BerkeleyDB among forked children
Message-Id: <0JqdnWjvc7mT0VfUnZ2dnUVZ8tyWnZ2d@giganews.com>
Hello,
Using BerkeleyDB in Perl 5.8.8 on a FreeBSD system, I am applying its tied
hashes inside forked children of a daemon, as a means of IPC. This works
great, except that for every child, when it forks, I currently set the
environment and initialize the databases, like:
if (not eval {$env = new BerkeleyDB::Env
-Cachesize => 16777216,
-Home => '/var/db/Berkeley',
-Flags => DB_CREATE|DB_INIT_CDB|DB_INIT_MPOOL}) {
log_error ((($_ = $BerkeleyDB::Error) ? ($_) : ($!)));
} elsif (not eval {tie %whitelisted, 'BerkeleyDB::Hash',
...
Etc. I wonder, is this really necessary? For one, I'm thinking it wreaks
havoc on the Cache, as re-initializing a cache for each child seems rather
pointless under these circumstances. Could I not just tie these databases
in the parent once, and then reuse them per child? I know for MySQL
connections this certainly goes wrong.
My main point just is, that I would like to retain the use of a shared
Cache among the forking children. If anyone knows how to do such a thing,
I'd appreciate hearing about it.
Thanks.
------------------------------
Date: Wed, 25 Mar 2009 01:58:14 -0700 (PDT)
From: Krishna Chaitanya <schaitan@gmail.com>
Subject: Typeglobs vs References
Message-Id: <66ac7bb3-6672-4551-8c54-5e0e6da92a18@b9g2000prd.googlegroups.com>
Hi, i've been reading Programming in Perl and perldata, perlref, etc
for understanding typeglobs and how they relate to references.
Frankly, i found the material a bit daunting for someone who's just
started in perl. In many places, I found statements to the effect that
typeglobs and references can be used interchangeably. How is this
possible? Can any1 pls point me to easier articles/tutorials which
give a step-by-step explanation? any examples that you can rig up to
clarify this?
Thanks a lot...
------------------------------
Date: Wed, 25 Mar 2009 09:27:42 GMT
From: sln@netherlands.com
Subject: Re: Typeglobs vs References
Message-Id: <92ujs4db4qut49691bqf7ks5u05ip271hj@4ax.com>
On Wed, 25 Mar 2009 01:58:14 -0700 (PDT), Krishna Chaitanya <schaitan@gmail.com> wrote:
>Hi, i've been reading Programming in Perl and perldata, perlref, etc
>for understanding typeglobs and how they relate to references.
>Frankly, i found the material a bit daunting for someone who's just
>started in perl. In many places, I found statements to the effect that
>typeglobs and references can be used interchangeably. How is this
>possible? Can any1 pls point me to easier articles/tutorials which
>give a step-by-step explanation? any examples that you can rig up to
>clarify this?
>
>Thanks a lot...
Why don't you stay away from typeglobs. Then you understand references
completely and are now moving on to typeglobs as a beginniner, or have you
learned typeglobs first?
-sln
------------------------------
Date: Wed, 25 Mar 2009 08:18:01 -0700 (PDT)
From: Krishna Chaitanya <schaitan@gmail.com>
Subject: Re: Typeglobs vs References
Message-Id: <eb0f0b8f-7031-42de-b8f4-a1582f6db453@a5g2000pre.googlegroups.com>
Learned references and their uses in creating data structures. Now
moving onto typeglobs...
------------------------------
Date: Wed, 25 Mar 2009 15:11:20 +0000 (UTC)
From: tmcd@panix.com (Tim McDaniel)
Subject: Re: what is the return value type of !1 ?
Message-Id: <gqdhio$j52$1@reader1.panix.com>
In article <slrngsjaq7.a7i.nospam-abuse@chorin.math.berkeley.edu>,
Ilya Zakharevich <nospam-abuse@ilyaz.org> wrote:
>On 2009-03-24, Tim McDaniel <tmcd@panix.com> wrote:
>> That can be stated more precisely. Luckily, "man perlsyn" does.
>
>... wrongly (as goes with the most of current Perl docs)...
>
>> There are actually 5 things that are treated as false in a boolean
>> context, and !(something true) has a special value:
>>
>> Truth and Falsehood
>>
>> The number 0, the strings '0' and '', the empty list "()", and
>> "undef" are all false in a boolean context. All other values
>> are true.
>
>Wrong.
I would like to learn more about Perl, so would you please explain
what is correct?
>> Negation of a true value by "!" or "not" returns a special
>> false value. When evaluated as a string it is treated as '',
>> but as a number, it is treated as 0.
>
>There is nothing especially "special" about the returned value
>(unless one noticed that it is the same value for all statements
>returning FALSE).
Well, as the examples showed, the value prints as a null string --
but, unlike "", it does not throw a warning under "-w" when used in
arithmetic. I don't know of any other value that has those
properties. Why do you write that it's not "special"?
--
Tim McDaniel, tmcd@panix.com
------------------------------
Date: Wed, 25 Mar 2009 16:27:09 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: what is the return value type of !1 ?
Message-Id: <tj2q96-gm1.ln1@osiris.mauzo.dyndns.org>
Quoth Ilya Zakharevich <nospam-abuse@ilyaz.org>:
> On 2009-03-24, Tim McDaniel <tmcd@panix.com> wrote:
>
> > Negation of a true value by "!" or "not" returns a special
> > false value. When evaluated as a string it is treated as '', but
> > as a number, it is treated as 0.
>
> There is nothing especially "special" about the returned value (unless
> one noticed that it is the same value for all statements returning FALSE).
Well, it's a dualvar, which is reasonably special. It is possible to
create an equivalent dualvar with
use Scalar::Util;
my $false = dualvar 0, "";
Ben
------------------------------
Date: Wed, 25 Mar 2009 11:59:04 -0500
From: Tad J McClellan <tadmc@seesig.invalid>
Subject: Re: what is the return value type of !1 ?
Message-Id: <slrngskomo.3mr.tadmc@tadmc30.sbcglobal.net>
Tim McDaniel <tmcd@panix.com> wrote:
> In article <slrngsjaq7.a7i.nospam-abuse@chorin.math.berkeley.edu>,
> Ilya Zakharevich <nospam-abuse@ilyaz.org> wrote:
>>On 2009-03-24, Tim McDaniel <tmcd@panix.com> wrote:
>>> That can be stated more precisely. Luckily, "man perlsyn" does.
>>
>>... wrongly (as goes with the most of current Perl docs)...
>>
>>> There are actually 5 things that are treated as false in a boolean
^^^^^^^^
>>> context, and !(something true) has a special value:
>>>
>>> Truth and Falsehood
>>>
>>> The number 0, the strings '0' and '', the empty list "()", and
^^^^^^^^^^^^^^^^^^^
>>> "undef" are all false in a boolean context. All other values
>>> are true.
>>
>>Wrong.
>
> I would like to learn more about Perl, so would you please explain
> what is correct?
I dunno if this is what Ilya had in mind, but the empty list
is most certainly not a false value.
Boolean context is a (special kind of) scalar context
unless ( warn wantarray ? "list context\n" : "scalar context\n" ) {
print "false value\n";
}
(prints only "scalar context")
and
there's no such thing as a list in scalar context (perlfaq4.pod)
eg.
unless ( () ) {
print "false value\n";
}
There is no empty list there, merely some parenthesis.
(parens are not a "list constructor". You very often see lists in
parens but that is for precedence reasons.
)
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.noitatibaher\100cmdat/"
------------------------------
Date: Wed, 25 Mar 2009 05:43:41 -0700 (PDT)
From: Klaus <klaus03@gmail.com>
Subject: XML::Reader - request for comments
Message-Id: <51f9db34-069f-445a-87dc-61cd0dcd424b@y9g2000yqg.googlegroups.com>
I have released the module XML::Reader to CPAN:
see http://search.cpan.org/~keichner/XML-Reader-0.01/
I would like to ask for comments, suggestions, improvements, code-
reviews, etc... for that module.
--
Klaus
------------------------------
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 V11 Issue 2296
***************************************
