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Website Programming in PHP / MYSQL
ip2long
(PHP 4, PHP 5)
ip2long — Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address
Description
The function ip2long() generates an IPv4 Internet network address from its Internet standard format (dotted string) representation.
ip2long() will also work with non-complete IP addresses. Read » http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/libs/commtrf2/inet_addr.htm for more info.
Parameters
- ip_address
-
A standard format address.
Return Values
Returns the IPv4 address or FALSE if ip_address is invalid.
ChangeLog
| Version | Description |
|---|---|
| 5.0.0 | Prior to this version, ip2long() returned -1 on failure. |
Examples
Example #1 ip2long() Example
<?php
$ip = gethostbyname('www.example.com');
$out = "The following URLs are equivalent:<br />\n";
$out .= 'http://www.example.com/, http://' . $ip . '/, and http://' . sprintf("%u", ip2long($ip)) . "/<br />\n";
echo $out;
?>
Example #2 Displaying an IP address
This second example shows how to print a converted address with the printf() function in both PHP 4 and PHP 5:
<?php
$ip = gethostbyname('www.example.com');
$long = ip2long($ip);
if ($long == -1 || $long === FALSE) {
echo 'Invalid IP, please try again';
} else {
echo $ip . "\n"; // 192.0.34.166
echo $long . "\n"; // -1073732954
printf("%u\n", ip2long($ip)); // 3221234342
}
?>
Example #3 IP validation
ip2long() should not be used as the sole form of IP validation. Combine it with long2ip():
<?php
// make sure IPs are valid. also converts a non-complete IP into
// a proper dotted quad as explained below.
$ip = long2ip(ip2long("127.0.0.1")); // "127.0.0.1"
$ip = long2ip(ip2long("10.0.0")); // "10.0.0.0"
$ip = long2ip(ip2long("10.0.256")); // "10.0.1.0"
?>
Notes
Note: Because PHP's integer type is signed, and many IP addresses will result in negative integers, you need to use the "%u" formatter of sprintf() or printf() to get the string representation of the unsigned IP address.
Note: ip2long() will return FALSE for the IP 255.255.255.255 in PHP 5 <= 5.0.2. It was fixed in PHP 5.0.3 where it returns -1 (same as PHP 4).
