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Homework and Emergencies Homework & Coursework Questions program to send messages to parent using pipes and select system call Post 302575616 by ripssingh on Tuesday 22nd of November 2011 07:58:52 AM
Old 11-22-2011
program to send messages to parent using pipes and select system call

Write a program using select, which will create some number of child processes that continuously send text messages to the parent process using pipes. Each child has its own pipe that it uses to communicate with the parent. The parent uses select () to decide what pipes should be processed to display text messages. Make all error checks in the program

Last edited by ripssingh; 11-22-2011 at 09:00 AM.. Reason: spelling mistake
 

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Mojo::DOM::CSS(3pm)					User Contributed Perl Documentation				       Mojo::DOM::CSS(3pm)

NAME
Mojo::DOM::CSS - CSS3 selector engine SYNOPSIS
use Mojo::DOM::CSS; # Select elements from DOM tree my $css = Mojo::DOM::CSS->new(tree => $tree); my $elements = $css->select('h1, h2, h3'); DESCRIPTION
Mojo::DOM::CSS is the CSS3 selector engine used by Mojo::DOM. SELECTORS
All CSS3 selectors that make sense for a standalone parser are supported. "*" Any element. my $all = $css->select('*'); "E" An element of type "E". my $title = $css->select('title'); "E[foo]" An "E" element with a "foo" attribute. my $links = $css->select('a[href]'); "E[foo="bar"]" An "E" element whose "foo" attribute value is exactly equal to "bar". my $fields = $css->select('input[name="foo"]'); "E[foo~="bar"]" An "E" element whose "foo" attribute value is a list of whitespace-separated values, one of which is exactly equal to "bar". my $fields = $css->select('input[name~="foo"]'); "E[foo^="bar"]" An "E" element whose "foo" attribute value begins exactly with the string "bar". my $fields = $css->select('input[name^="f"]'); "E[foo$="bar"]" An "E" element whose "foo" attribute value ends exactly with the string "bar". my $fields = $css->select('input[name$="o"]'); "E[foo*="bar"]" An "E" element whose "foo" attribute value contains the substring "bar". my $fields = $css->select('input[name*="fo"]'); "E:root" An "E" element, root of the document. my $root = $css->select(':root'); "E:checked" A user interface element "E" which is checked (for instance a radio-button or checkbox). my $input = $css->select(':checked'); "E:empty" An "E" element that has no children (including text nodes). my $empty = $css->select(':empty'); "E:nth-child(n)" An "E" element, the "n-th" child of its parent. my $third = $css->select('div:nth-child(3)'); my $odd = $css->select('div:nth-child(odd)'); my $even = $css->select('div:nth-child(even)'); my $top3 = $css->select('div:nth-child(-n+3)'); "E:nth-last-child(n)" An "E" element, the "n-th" child of its parent, counting from the last one. my $third = $css->select('div:nth-last-child(3)'); my $odd = $css->select('div:nth-last-child(odd)'); my $even = $css->select('div:nth-last-child(even)'); my $bottom3 = $css->select('div:nth-last-child(-n+3)'); "E:nth-of-type(n)" An "E" element, the "n-th" sibling of its type. my $third = $css->select('div:nth-of-type(3)'); my $odd = $css->select('div:nth-of-type(odd)'); my $even = $css->select('div:nth-of-type(even)'); my $top3 = $css->select('div:nth-of-type(-n+3)'); "E:nth-last-of-type(n)" An "E" element, the "n-th" sibling of its type, counting from the last one. my $third = $css->select('div:nth-last-of-type(3)'); my $odd = $css->select('div:nth-last-of-type(odd)'); my $even = $css->select('div:nth-last-of-type(even)'); my $bottom3 = $css->select('div:nth-last-of-type(-n+3)'); "E:first-child" An "E" element, first child of its parent. my $first = $css->select('div p:first-child'); "E:last-child" An "E" element, last child of its parent. my $last = $css->select('div p:last-child'); "E:first-of-type" An "E" element, first sibling of its type. my $first = $css->select('div p:first-of-type'); "E:last-of-type" An "E" element, last sibling of its type. my $last = $css->select('div p:last-of-type'); "E:only-child" An "E" element, only child of its parent. my $lonely = $css->select('div p:only-child'); "E:only-of-type" An "E" element, only sibling of its type. my $lonely = $css->select('div p:only-of-type'); "E.warning" my $warning = $css->select('div.warning'); An "E" element whose class is "warning". "E#myid" my $foo = $css->select('div#foo'); An "E" element with "ID" equal to "myid". E:not(s) An "E" element that does not match simple selector "s". my $others = $css->select('div p:not(:first-child)'); "E F" An "F" element descendant of an "E" element. my $headlines = $css->select('div h1'); "E > F" An "F" element child of an "E" element. my $headlines = $css->select('html > body > div > h1'); "E + F" An "F" element immediately preceded by an "E" element. my $second = $css->select('h1 + h2'); "E ~ F" An "F" element preceded by an "E" element. my $second = $css->select('h1 ~ h2'); "E, F, G" Elements of type "E", "F" and "G". my $headlines = $css->select('h1, h2, h3'); "E[foo=bar][bar=baz]" An "E" element whose attributes match all following attribute selectors. my $links = $css->select('a[foo^="b"][foo$="ar"]'); ATTRIBUTES
Mojo::DOM::CSS implements the following attributes. "tree" my $tree = $css->tree; $css = $css->tree(['root', [qw(text lalala)]]); Document Object Model. METHODS
Mojo::DOM::CSS inherits all methods from Mojo::Base and implements the following new ones. "select" my $results = $css->select('head > title'); Run CSS3 selector against "tree". SEE ALSO
Mojolicious, Mojolicious::Guides, <http://mojolicio.us>. perl v5.14.2 2012-09-05 Mojo::DOM::CSS(3pm)
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