超越PHP - Exceed PHP: gethostbyname

Description

string gethostbyname ( string hostname)

Returns the IP address of the Internet host specified by hostname or a string containing the unmodified hostname on failure.

例子 1. A simple gethostbyname() example

<?php $ip = gethostbyname('www.example.com'); echo $ip; ?>

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gethostbyname

sjohnson at fuzzygroup dot com
17-Mar-2002 02:27

<?php

//script to see if host exists on
Internet

//following up on the above point about host name

//checking and SQL timeouts, run this test script
//and see how long
it takes for 2nd call to 
//hostname check to fail
//NOTE -- not
PHP's fault -- nature of DNS 

//A known good dns name (my
own)
	$nametotest = "fuzzygroup.com";
	
//Call address
test function 
	testipaddress($nametotest);

//A known bad name
(trust me)
	$nametotest = "providence.mascot.com";
//Call
address test function
	testipaddress($nametotest);
	
//ip address
checking function
//for real use should have a return value but example
code
function testipaddress ($nametotest) {
	$ipaddress =
$nametotest;
	$ipaddress = gethostbyname($nametotest);
	if
($ipaddress == $nametotest) {
		echo "No ip address for host, so
host "
		     . "not currently available in DNS and
"
		     . "probably offline for some
time
";
	}
	else {
		echo "good hostname, ipaddress =
$ipaddress
";
	}
}

//Recommended fix for sql
applications: 
// store url to temporary table 
// run second process
periodically to 
// check urls and update main table
?>

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