revision:
Syntax: checkdnsrr(host, type)
Parameter values:
host : required. Specifies an IP address or host name to check.
type : optional. Specifies the type. Can be one of the following: A, MX (default), NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR,TXT, ANY
example: check DNS records
<?php
$domain="w3schools.com";
if(checkdnsrr($domain,"MX")) {
echo "Passed";
} else {
echo "Failed";
}
?>
Syntax: closelog()
example:
<?php
function _log($text) {
openlog("phperrors", LOG_PID | LOG_PERROR);
syslog(LOG_ERR, $text);
closelog();
}
?>
deprecated and removed in PHP 5.4
Syntax: dns_check_record(host, type)
Parameter values:
host : required. Specifies an IP address or host name to check.
type : optional. Specifies the type. Can be one of the following: A, MX (default), NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR,TXT, ANY
example:
<?php
$domain="w3schools.com";
if(dns_check_record($domain,"MX")) {
echo "Passed";
} else {
echo "Failed";
}
?>
Syntax: dns_get_mx(host, mxhosts, weight)
Parameter values:
host : required. Specifies the host name
mxhosts : required. An array that specifies a list of MX records found
weight : optional. An array that specifies the weight information gathered
example:
<?php
$domain="w3schools.com";
if(dns_get_mx($domain,$mx_details)){
foreach($mx_details as $key=>$value){
echo "$key => $value <br>";
}
}
?>
Syntax: dns_get_record(hostname, type, authns, addtl, raw)
Parameter values:
hostname : required. Specifies a hostname (like "www.w3schools.com")
type : optional. Specifies the resource record type to search for. Can be one of the following: DNS_A, DNS_CNAME, DNS_HINFO,DNS_CAA, DNS_MX, DNS_NS, DNS_PTR, DNS_SOA, DNS_TXT, DNS_AAAA, DNS_SRV, DNS_NAPTR, DNS_A6, DNS_ALL, DNS_ANY (default)
authns : optional. Passed by reference and, if set, it will be populated with Resource Records for the Authoritative Name Servers
addtl : optional. Passed by reference and, if set, it will be populated with any Additional Records
example:
<?php
print_r(dns_get_record("w3schools.com", DNS_MX));
?>
Syntax: fsockopen(hostname, port, errno, errstr, timeout)
Parameter values:
hostname : required. Specifies a hostname (like "www.w3schools.com"). ssl:// or tls:// works over TCP/IP to connect to the remote host
port : optional. Specifies the port number. Use -1 for transports that do not use ports, like unix://
errno : optional. Specifies the system level error number
errstr : optional. Specifies the error message as a string
timeout : optional. Specifies the connection timeout (in seconds)
example:
<?php
$fp = fsockopen("www.lwitters.com", 80, $errno, $errstr, 20);
if (!$fp) {
echo "$errstr ($errno)<br>";
} else {
$out = "GET / HTTP/1.1\r\n";
$out .= "Host: www.w3schools.com\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
echo fgets($fp, 128);
}
fclose($fp);
}
?>
Syntax: gethostbyaddr(ipaddress)
Parameter values:
ipaddress : required. Specifies an IP address
example:
<?php
$host = gethostbyaddr($_SERVER["REMOTE_ADDR"]);
echo $host;
?>
Syntax: gethostbyname(hostname)
Parameter values:
hostname : required. Specifies a hostname (like "www.w3schools.com")
example:
<?php
$ip = gethostbyname("www.w3schools.com");
echo $ip;
?>
Syntax: gethostbynamel(hostname)
Parameter values:
hostname : required. Specifies a hostname (like "www.w3schools.com")
example:
<?php
$hostlist = gethostbynamel("www.w3schools.com");
print_r($hostlist);
?>
Syntax: gethostname()
example:
<?php
echo gethostname();
?>
Syntax: getmxrr(host, mxhosts, weight)
Parameter values:
host : required. Specifies the host name
mxhosts : required. An array that specifies a list of MX records found
weight : otional. An array that specifies the weight information gathered
example:
<?php
$domain="w3schools.com";
if(getmxrr($domain,$mx_details)){
foreach($mx_details as $key=>$value){
echo "$key => $value <br>";
}
}
?>
Syntax: getprotobyname(protocolname)
Parameter values:
protocolname : required. Specifies a protocol name (like "tcp")
example:
<?php
$protocolnum = getprotobyname("tcp");
echo $protocolnum;
?>
Syntax: getprotobynumber(protocolnumber)
Parameter values:
protocolnumber : required. Specifies a protocol number (like 17)
example:
<?php
$protocolname = getprotobynumber(6);
echo $protocolname;
?>
Syntax: getservbyname(service, protocol)
Parameter values:
service : required. Specifies the Internet service name (like "http")
protocol : required. Specifies a protocol name (like "tcp" or "udp")
example:
<?php
$portnum = getservbyname("http", "tcp");
echo $portnum;
?>
Syntax: getservbyport(port, protocol)
Parameter values:
port : required. Specifies the port number (like 80)
protocol : required. Specifies a protocol name (like "tcp" or "udp")
example:
<?php
$intservname = getservbyport(80, "tcp");
echo $intservname;
?>
Syntax: header_register_callback(callback)
Parameter values:
callback : required. Specifies a callback function
example:
Syntax: header_remove(headername)
Parameter values:
headername : optional. Specifies a header name to be removed. If omitted, all previously set headers are removed
example:
<?php
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Cache-Control: no-cache");
header("Pragma: no-cache");
header_remove("Pragma");
?>
Syntax: header(header, replace, http_response_code)
Parameter values:
header : required. Specifies the header string to send
replace : optional. Indicates whether the header should replace a previous similar header or add a new header of the same type. Default is TRUE (will replace). FALSE allows multiple headers of the same type
http_response_code : optional. Forces the HTTP response code to the specified value
It is important to notice that the header() function must be called before any actual output is sent!
example:
<?php
// Date in the past
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Cache-Control: no-cache");
header("Pragma: no-cache");
?>
example:
<?php
setcookie("TestCookie","SomeValue");
header("X-Sample-Test: foo");
header("Content-type: text/plain");
?>
<?php
var_dump(headers_list());
?>
Syntax: headers_sent(file,line)
Parameter values:
file : optional. If the file and line parameters are set, headers_sent() will put the PHP source file name and line number where output started in the file and line variables
line : optional. Specifies the line number where the output started
example:
<?php
if (!headers_sent()) {
header("Location: https://www.w3schools.com/");
exit;
}
?>
Syntax: http_response_code(code)
Parameter values:
code : optional. Specifies a response code (like 404)
example:
<?php
http_response_code(404);
?>
Syntax: inet_ntop(address)
Parameter values:
address : required. Specifies a 32bit IPv4 or 128bit IPv6 address
example:
<?php
$addr = chr(127) . chr(0) . chr(1) . chr(1);
$exp = inet_ntop($addr);
echo $exp;
?>
Syntax: inet_pton(address)
Parameter values:
address : required. Specifies a readable IP address
example:
<?php
$addr = inet_pton("127.0.1.1");
echo $addr;
?>
Syntax: ip2long(address)
Parameter values:
address : required. Specifies a readable IP address
example:
<?php
$ip = gethostbyname("www.w3schools.com");
$out = "The following URLs are equivalent:<br>";
$out .= "https://www.w3schools.com/, https://" . $ip . "/, and https://" . sprintf("%u", ip2long($ip)) . "/";
echo $out;
?>
Syntax: long2ip(address)
Parameter values:
address : required. Specifies a long integer that represents an IP address
example:
<?php
echo(long2ip(344294967296));
?>
Syntax: openlog(ident, option, facility)
Parameter values:
ident : required. Specifies a string ident that is added to each message
option : required. Specifies what logging options will be used when generating a log message. Can be one or more of the following options (separated with |): LOG_CONS, LOG_NDELAY, LOG_ODELAY, LOG_PERROR, LOG_PID
facility : required. Specifies what type of program is logging the message:LOG_AUTH, LOG_AUTHPRIV, LOG_CRON, LOG_DAEMON, LOG_KERN, LOG_LOCAL0...LOG_LOCAL7, LOG_LPR, LOG_MAIL, LOG_NEWS, LOG_SYSLOG, LOG_USER - (is the only valid log type for Windows OS), LOG_UUCP
example:
<?php
function _log($text) {
openlog("phperrors", LOG_PID | LOG_PERROR);
syslog(LOG_ERR, $text);
closelog();
}
?>
Syntax: pfsockopen(hostname, port, errno, errstr, timeout)
Parameter values:
hostname : required. Specifies a hostname (like "www.w3schools.com"). ssl:// or tls:// works over TCP/IP to connect to the remote host
port : optional. Specifies the port number. Use -1 for transports that do not use ports, like unix://
errno : optional. Specifies the system level error number
errstr : optional. Specifies the error message as a string
timeout : optional. Specifies the connection timeout (in seconds)
example:
The document has moved here.
<?php
$fp = pfsockopen("www.lwitters.com", 80, $errno, $errstr, 20);
if (!$fp) {
echo "$errstr ($errno)<br>";
} else {
$out = "GET / HTTP/1.1\r\n";
$out .= "Host: www.lwitters.com\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
echo fgets($fp, 128);
}
fclose($fp);
}
?>
Syntax: setcookie(name, value, expire, path, domain, secure, httponly);
Parameter values:
name : required. Specifies the name of the cookie
value : optional. Specifies the value of the cookie
expire : optional. Specifies when the cookie expires. The value: time()+86400*30, will set the cookie to expire in 30 days. If this parameter is omitted or set to 0, the cookie will expire at the end of the session (when the browser closes). Default is 0
path : optional. Specifies the server path of the cookie. If set to "/", the cookie will be available within the entire domain. If set to "/php/", the cookie will only be available within the php directory and all sub-directories of php. The default value is the current directory that the cookie is being set in
domain : optional. Specifies the domain name of the cookie. To make the cookie available on all subdomains of example.com, set domain to "example.com". Setting it to www.example.com will make the cookie only available in the www subdomain
secure : optional. Specifies whether or not the cookie should only be transmitted over a secure HTTPS connection. TRUE indicates that the cookie will only be set if a secure connection exists. Default is FALSE
httponly : optional. If set to TRUE the cookie will be accessible only through the HTTP protocol (the cookie will not be accessible by scripting languages). This setting can help to reduce identity theft through XSS attacks. Default is FALSE
example:
<?php
$cookie_name = "user";
$cookie_value = "John Doe";
setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day
?>
<html>
<body>
<?php
if(!isset($_COOKIE[$cookie_name])) {
echo "Cookie named '" . $cookie_name . "' is not set!";
} else {
echo "Cookie '" . $cookie_name . "' is set!<br>";
echo "Value is: " . $_COOKIE[$cookie_name];
}
?>
Syntax: setrawcookie(name, value, expire, path, domain, secure);
Parameter values:
name : required. Specifies the name of the cookie
value : optional. Specifies the value of the cookie
expire : optional. Specifies when the cookie expires. The value: time()+86400*30, will set the cookie to expire in 30 days. If this parameter is omitted or set to 0, the cookie will expire at the end of the session (when the browser closes). Default is 0
path : optional. Specifies the server path of the cookie. If set to "/", the cookie will be available within the entire domain. If set to "/php/", the cookie will only be available within the php directory and all sub-directories of php. The default value is the current directory that the cookie is being set in
domain : optional. Specifies the domain name of the cookie. To make the cookie available on all subdomains of example.com, set domain to "example.com". Setting it to www.example.com will make the cookie only available in the www subdomain
secure : optional. Specifies whether or not the cookie should only be transmitted over a secure HTTPS connection. TRUE indicates that the cookie will only be set if a secure connection exists. Default is FALSE
example:
<?php
$cookie_name = "user";
$cookie_value = "John";
setrawcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/");
// 86400 = 1 day
?>
<html>
<body>
<?php
echo "Cookie is set.";
?>
Syntax: syslog(priority, message)
Parameter values:
priority : required. Specifies ... Can be one of the following options:LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG
message : required. Specifies the message to send
example:
<?php
function _log($text) {
openlog("phperrors", LOG_PID | LOG_PERROR);
syslog(LOG_ERR, $text);
closelog();
}
?>