Delicious Bookmark this on Delicious Share on Facebook SlashdotSlashdot It! Digg! Digg

PHP : Function Reference : Error Handling and Logging Functions

Error Handling and Logging Functions


These are functions dealing with error handling and logging. They allow you to define your own error handling rules, as well as modify the way the errors can be logged. This allows you to change and enhance error reporting to suit your needs.

With the logging functions, you can send messages directly to other machines, to an email (or email to pager gateway!), to system logs, etc., so you can selectively log and monitor the most important parts of your applications and websites.

The error reporting functions allow you to customize what level and kind of error feedback is given, ranging from simple notices to customized functions returned during errors.


No external libraries are needed to build this extension.


There is no installation needed to use these functions; they are part of the PHP core.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 80. Errors and Logging Configuration Options

Name Default Changeable Changelog
error_reporting NULL PHP_INI_ALL  
display_errors "1" PHP_INI_ALL  
display_startup_errors "0" PHP_INI_ALL Available since PHP 4.0.3.
log_errors "0" PHP_INI_ALL  
log_errors_max_len "1024" PHP_INI_ALL Available since PHP 4.3.0.
ignore_repeated_errors "0" PHP_INI_ALL Available since PHP 4.3.0.
ignore_repeated_source "0" PHP_INI_ALL Available since PHP 4.3.0.
report_memleaks "1" PHP_INI_ALL Available since PHP 4.3.0.
track_errors "0" PHP_INI_ALL  
html_errors "1" PHP_INI_ALL PHP_INI_SYSTEM in PHP <= 4.2.3. Available since PHP 4.0.2.
docref_root "" PHP_INI_ALL Available since PHP 4.3.0.
docref_ext "" PHP_INI_ALL Available since PHP 4.3.2.
error_prepend_string NULL PHP_INI_ALL  
error_append_string NULL PHP_INI_ALL  
error_log NULL PHP_INI_ALL  
warn_plus_overloading NULL   This option is no longer available as of PHP 4.0.0

For further details and definitions of the PHP_INI_* constants, see the Appendix I, php.ini directives.

Here's a short explanation of the configuration directives.

error_reporting integer

Set the error reporting level. The parameter is either an integer representing a bit field, or named constants. The error_reporting levels and constants are described in Predefined Constants, and in php.ini. To set at runtime, use the error_reporting() function. See also the display_errors directive.

In PHP 4 and PHP 5 the default value is E_ALL & ~E_NOTICE. This setting does not show E_NOTICE level errors. You may want to show them during development.


Enabling E_NOTICE during development has some benefits. For debugging purposes: NOTICE messages will warn you about possible bugs in your code. For example, use of unassigned values is warned. It is extremely useful to find typos and to save time for debugging. NOTICE messages will warn you about bad style. For example, $arr[item] is better to be written as $arr['item'] since PHP tries to treat "item" as constant. If it is not a constant, PHP assumes it is a string index for the array.


In PHP 5 a new error level E_STRICT is available. As E_STRICT is not included within E_ALL you have to explicitly enable this kind of error level. Enabling E_STRICT during development has some benefits. STRICT messages will help you to use the latest and greatest suggested method of coding, for example warn you about using deprecated functions.

PHP Constants outside of PHP:

Using PHP Constants outside of PHP, like in httpd.conf, will have no useful meaning so in such cases the integer values are required. And since error levels will be added over time, the maximum value (for E_ALL) will likely change. So in place of E_ALL consider using a larger value to cover all bit fields from now and well into the future, a numeric value like 2147483647.

In PHP 3, the default setting is (E_ERROR | E_WARNING | E_PARSE), meaning the same thing. Note, however, that since constants are not supported in PHP 3's php3.ini, the error_reporting setting there must be numeric; hence, it is 7.

display_errors string

This determines whether errors should be printed to the screen as part of the output or if they should be hidden from the user.

Value "stderr" sends the errors to stderr instead of stdout. The value is available as of PHP 5.2.4. In earlier versions, this directive was of type boolean.


This is a feature to support your development and should never be used on production systems (e.g. systems connected to the internet).


Although display_errors may be set at runtime (with ini_set()), it won't have any affect if the script has fatal errors. This is because the desired runtime action does not get executed.

display_startup_errors boolean

Even when display_errors is on, errors that occur during PHP's startup sequence are not displayed. It's strongly recommended to keep display_startup_errors off, except for debugging.

log_errors boolean

Tells whether script error messages should be logged to the server's error log or error_log. This option is thus server-specific.


You're strongly advised to use error logging in place of error displaying on production web sites.

log_errors_max_len integer

Set the maximum length of log_errors in bytes. In error_log information about the source is added. The default is 1024 and 0 allows to not apply any maximum length at all. This length is applied to logged errors, displayed errors and also to $php_errormsg.

When an integer is used, the value is measured in bytes. You may also use shorthand notation as described in this FAQ.

ignore_repeated_errors boolean

Do not log repeated messages. Repeated errors must occur in the same file on the same line until ignore_repeated_source is set true.

ignore_repeated_source boolean

Ignore source of message when ignoring repeated messages. When this setting is On you will not log errors with repeated messages from different files or sourcelines.

report_memleaks boolean

If this parameter is set to Off, then memory leaks will not be shown (on stdout or in the log). This has only effect in a debug compile, and if error_reporting includes E_WARNING in the allowed list

track_errors boolean

If enabled, the last error message will always be present in the variable $php_errormsg.

html_errors boolean

Turn off HTML tags in error messages. The new format for HTML errors produces clickable messages that direct the user to a page describing the error or function in causing the error. These references are affected by docref_root and docref_ext.

docref_root string

The new error format contains a reference to a page describing the error or function causing the error. In case of manual pages you can download the manual in your language and set this ini directive to the URL of your local copy. If your local copy of the manual can be reached by '/manual/' you can simply use docref_root=/manual/. Additional you have to set docref_ext to match the fileextensions of your copy docref_ext=.php. it is possible to use external references. for example you can use docref_root=http://manual/en/ or docref_root=" &"

Most of the time you want the docref_root value to end with a slash '/'. But see the second example above which does not have nor need it.


This is a feature to support your development since it makes it easy to lookup a function description. However it should never be used on production systems (e.g. systems connected to the internet).

docref_ext string

See docref_root.


The value of docref_ext must begin with a dot '.'.

error_prepend_string string

String to output before an error message.

error_append_string string

String to output after an error message.

error_log string

Name of the file where script errors should be logged. The file should be writable by the web server's user. If the special value syslog is used, the errors are sent to the system logger instead. On Unix, this means syslog(3) and on Windows NT it means the event log. The system logger is not supported on Windows 95. See also: syslog(). If this directive is not set, errors are sent to the SAPI error logger. For example, it is an error log in Apache or stderr in CLI.

warn_plus_overloading boolean

If enabled, this option makes PHP output a warning when the plus (+) operator is used on strings. This is to make it easier to find scripts that need to be rewritten to using the string concatenator instead (.). This option doesn't exist as of PHP 4.

Predefined Constants

The constants below are always available as part of the PHP core.


You may use these constant names in php.ini but not outside of PHP, like in httpd.conf, where you'd use the bitmask values instead.

Table 81. Errors and Logging

Value Constant Description Note
1 E_ERROR (integer) Fatal run-time errors. These indicate errors that can not be recovered from, such as a memory allocation problem. Execution of the script is halted.  
2 E_WARNING (integer) Run-time warnings (non-fatal errors). Execution of the script is not halted.  
4 E_PARSE (integer) Compile-time parse errors. Parse errors should only be generated by the parser.  
8 E_NOTICE (integer) Run-time notices. Indicate that the script encountered something that could indicate an error, but could also happen in the normal course of running a script.  
16 E_CORE_ERROR (integer) Fatal errors that occur during PHP's initial startup. This is like an E_ERROR, except it is generated by the core of PHP. since PHP 4
32 E_CORE_WARNING (integer) Warnings (non-fatal errors) that occur during PHP's initial startup. This is like an E_WARNING, except it is generated by the core of PHP. since PHP 4
64 E_COMPILE_ERROR (integer) Fatal compile-time errors. This is like an E_ERROR, except it is generated by the Zend Scripting Engine. since PHP 4
128 E_COMPILE_WARNING (integer) Compile-time warnings (non-fatal errors). This is like an E_WARNING, except it is generated by the Zend Scripting Engine. since PHP 4
256 E_USER_ERROR (integer) User-generated error message. This is like an E_ERROR, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4
512 E_USER_WARNING (integer) User-generated warning message. This is like an E_WARNING, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4
1024 E_USER_NOTICE (integer) User-generated notice message. This is like an E_NOTICE, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4
2048 E_STRICT (integer) Run-time notices. Enable to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code. since PHP 5
4096 E_RECOVERABLE_ERROR (integer) Catchable fatal error. It indicates that a probably dangerous error occured, but did not leave the Engine in an unstable state. If the error is not caught by a user defined handle (see also set_error_handler()), the application aborts as it was an E_ERROR. since PHP 5.2.0
8191 E_ALL (integer) All errors and warnings, as supported, except of level E_STRICT in PHP < 6. 6143 in PHP 5.2.x and 2047 previously

The above values (either numerical or symbolic) are used to build up a bitmask that specifies which errors to report. You can use the bitwise operators to combine these values or mask out certain types of errors. Note that only '|', '~', '!', '^' and '&' will be understood within php.ini, however, and that no bitwise operators will be understood within php3.ini.


Below we can see an example of using the error handling capabilities in PHP. We define an error handling function which logs the information into a file (using an XML format), and e-mails the developer in case a critical error in the logic happens.

Example 589. Using error handling in a script

// we will do our own error handling

// user defined error handling function
function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars)
// timestamp for the error entry
$dt = date("Y-m-d H:i:s (T)");

// define an assoc array of error string
   // in reality the only entries we should
   // consider are E_WARNING, E_NOTICE, E_USER_ERROR,
$errortype = array (
E_ERROR              => 'Error',
E_WARNING            => 'Warning',
E_PARSE              => 'Parsing Error',
E_NOTICE             => 'Notice',
E_CORE_ERROR         => 'Core Error',
E_CORE_WARNING       => 'Core Warning',
E_COMPILE_ERROR      => 'Compile Error',
E_COMPILE_WARNING    => 'Compile Warning',
E_USER_ERROR         => 'User Error',
E_USER_WARNING       => 'User Warning',
E_USER_NOTICE        => 'User Notice',
E_STRICT             => 'Runtime Notice',
E_RECOVERABLE_ERROR  => 'Catchable Fatal Error'
// set of errors for which a var trace will be saved
$user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE);
$err = "<errorentry>\n";
$err .= "\t<datetime>" . $dt . "</datetime>\n";
$err .= "\t<errornum>" . $errno . "</errornum>\n";
$err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n";
$err .= "\t<errormsg>" . $errmsg . "</errormsg>\n";
$err .= "\t<scriptname>" . $filename . "</scriptname>\n";
$err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";

   if (
in_array($errno, $user_errors)) {
$err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n";
$err .= "</errorentry>\n\n";
// for testing
   // echo $err;

   // save to the error log, and e-mail me if there is a critical user error
error_log($err, 3, "/usr/local/php4/error.log");
   if (
$errno == E_USER_ERROR) {
mail("", "Critical User Error", $err);

distance($vect1, $vect2)
   if (!
is_array($vect1) || !is_array($vect2)) {
trigger_error("Incorrect parameters, arrays expected", E_USER_ERROR);

   if (
count($vect1) != count($vect2)) {
trigger_error("Vectors need to be of the same size", E_USER_ERROR);

   for (
$i=0; $i<count($vect1); $i++) {
$c1 = $vect1[$i]; $c2 = $vect2[$i];
$d = 0.0;
       if (!
is_numeric($c1)) {
trigger_error("Coordinate $i in vector 1 is not a number, using zero",
$c1 = 0.0;
       if (!
is_numeric($c2)) {
trigger_error("Coordinate $i in vector 2 is not a number, using zero",
$c2 = 0.0;
$d += $c2*$c2 - $c1*$c1;

$old_error_handler = set_error_handler("userErrorHandler");

// undefined constant, generates a warning

// define some "vectors"
$a = array(2, 3, "foo");
$b = array(5.5, 4.3, -1.6);
$c = array(1, -3);

// generate a user error
$t1 = distance($c, $b) . "\n";

// generate another user error
$t2 = distance($b, "i am not an array") . "\n";

// generate a warning
$t3 = distance($a, $b) . "\n";


See Also

See also syslog().

Table of Contents

debug_backtrace — Generates a backtrace
debug_print_backtrace — Prints a backtrace
error_get_last — Get the last occurred error
error_log — Send an error message somewhere
error_reporting — Sets which PHP errors are reported
restore_error_handler — Restores the previous error handler function
restore_exception_handler — Restores the previously defined exception handler function
set_error_handler — Sets a user-defined error handler function
set_exception_handler — Sets a user-defined exception handler function
trigger_error — Generates a user-level error/warning/notice message
user_error — Alias of trigger_error()

Code Examples / Notes » ref.errorfunc

21-may-2005 12:20

When configuring your error log file in php.ini, you can use an absolute path or a relative path.  A relative path will be resolved based on the location of the generating script, and you'll get a log file in each directory you have scripts in.  If you want all your error messages to go to the same file, use an absolute path to the file.
In some application development methodologies, there is the concept of an application root directory, indicated by "/" (even on Windows).  However, PHP does not seem to have this concept, and using a "/" as the initial character in a log file path produces weird behavior on Windows.
If you are running on Windows and have set, in php.ini:
 error_log = "/php_error.log"
You will get some, but not all, error messages.  The file will appear at
and contain internally generated error messages, making it appear that error logging is working.  However, log messages requested by error_log() do NOT appear here, or anywhere else, making it appear that the code containing them did not get processed.
Apparently on Windows the internally generated errors will interpret "/" as "C:\" (or possibly a different drive if you have Windows installed elsewhere - I haven't tested this).  However, the error_log process apparently can't find "/" - understandably enough - and the message is dropped silently.


To add to Stephen's note about logging, I found that if I defined the error_log path to be the Apache error log folder (ie:  /var/log/httpd/php_error_log), it would still log to Apache's log, not the file I defined.
However, as soon as I moved the log to a location outside of the Apache error log folder, Apache obeyed my php.ini setting and began logging to the file I defined (ie: /var/log/php/php_error_log).
Platform: RHEL 4, Apache 2.0.55, PHP 5.2.2

giunta dot gaetano

Something to take care of: if track_errors is enabled, $php_errormsg will always be populated with error messages of warning (and possibly notice?) level, regardless of the error_reporting level set.


PHP5 only (only tested with php5.0).
If you, for some reason, prefer exceptions over errors and have your custom error handler (set_error_handler) wrap the error into an exception you have to be careful with your script.
Because if you, instead of just calling the exception handler, throws the exception, and having a custom exception handler (set_exception_handler). And an error is being triggered inside that exception handler, you will get a weird error:
"Fatal error: Exception thrown without a stack frame in Unknown on line 0"
This error is not particulary informative, is it? :)
This example below will cause this error.
class PHPErrorException extends Exception
private $context = null;
public function __construct
($code, $message, $file, $line, $context = null)
parent::__construct($message, $code);
$this->file = $file;
$this->line = $line;
$this->context = $context;
function error_handler($code, $message, $file, $line) {
throw new PHPErrorException($code, $message, $file, $line);
function exception_handler(Exception $e)
$errors = array(
       E_USER_ERROR => "User Error",
       E_USER_WARNING => "User Warning",
       E_USER_NOTICE => "User Notice",

echo $errors[$e->getCode()].': '.$e->getMessage().' in '.$e->getFile().
' on line '.$e->getLine()."\n";
echo $e->getTraceAsString();
// Throw exception with an /unkown/ error code.
throw new Exception('foo', 0);
There are however, easy fix for this as it's only cause is sloppy code.
Like one, directly call exception_handler from error_handler instead of throwing an exception. Not only does it remedy this problem, but it's also faster. Though this will cause a `regular` unhandled exception being printed and if only "designed" error messages are intended, this is not the ultimate solution.
So, what is there to do? Make sure the code in exception_handlers doesn't cause any errors! In this case a simple isset() would have solved it.
regards, C-A B.


Note the example code listed here calls date() every time this is called.   If you have a complex source base which calls the custom error handler often, it can end up taking quite a bit of time.  I ran a profiler on som code and discovered that 50% of the time was spent in the date function in this error handler.


It is totally possible to use debug_backtrace() inside an error handling function. Here, take a look:
function errorHandler( $errno, $errstr, $errfile, $errline, $errcontext)
 echo 'Into '.__FUNCTION__.'() at line '.__LINE__.
 "\n\n---ERRNO---\n". print_r( $errno, true).
 "\n\n---ERRSTR---\n". print_r( $errstr, true).
 "\n\n---ERRFILE---\n". print_r( $errfile, true).
 "\n\n---ERRLINE---\n". print_r( $errline, true).
 "\n\n---ERRCONTEXT---\n".print_r( $errcontext, true).
 "\n\nBacktrace of errorHandler()\n".
 print_r( debug_backtrace(), true);
function a( )
 //echo "a()'s backtrace\n".print_r( debug_backtrace(), true);
 asdfasdf; // oops
function b()
 //echo "b()'s backtrace\n".print_r( debug_backtrace(), true);
Into errorhandler() at line 9
Use of undefined constant asdfasdf - assumed 'asdfasdf'
Backtrace of errorHandler()
   [0] => Array
           [function] => errorhandler
           [args] => Array
                   [0] => 8
                   [1] => Use of undefined constant asdfasdf - assumed 'asdfasdf'
                   [2] => /home/theotek/test-1.php
                   [3] => 23
                   [4] => Array
   [1] => Array
           [file] => /home/theotek/test-1.php
           [line] => 23
           [function] => a
   [2] => Array
           [file] => /home/theotek/test-1.php
           [line] => 30
           [function] => a
           [args] => Array
   [3] => Array
           [file] => /home/theotek/test-1.php
           [line] => 33
           [function] => b
           [args] => Array
So, the first member of the backtrace's array is not really surprising, except from the missing "file" and "line" members.
The second member of the backtrace seem the be a hook inside the zend engine that is used to trigger the error.
Other members are the normal backtrace.


In Addition to the hint according error_reporting and display_errors in case that there is a global restriction that prevents showing the errors.
I tried the example of "petrov dot michael () gmail com" like this
error_reporting (E_ALL);
and it works great, but first I tried it without using the "include"-part. I pasted all at the beginning of my index.php and started it. This will NOT work.
Its highly IMPORTANT that the code to prove is included afterwards.
Hope it helps to prevent more #?!@%! errors. :-)=


if you cannot use php 5+ and if you do not know, when your administrator/provider will update to a newer php-version, this could be interesting. otherwise it surely is not. ;-)
if you use the example above "example 1: using error handling in a script" with a php version prior to php 5, the part
$errortype = array(
 // ...
 E_STRICT          => "Runtime Notice");?>
will throw a notice like
"Use of undefined constant E_STRICT - assumed 'E_STRICT'".
of course one could avoid this problem, with
if(defined('E_STRICT')) define('E_STRICT', 2048);
but this _could_ generate problems in future versions of php, if E_STRICT is set to 42 or something else.
for this reason i suggest
$errortype = array(
 E_ERROR           => 'error',
 E_WARNING         => 'warning',
 E_PARSE           => 'parsing error',
 E_NOTICE          => 'notice',
 E_CORE_ERROR      => 'core error',
 E_CORE_WARNING    => 'core warning',
 E_COMPILE_ERROR   => 'compile error',
 E_COMPILE_WARNING => 'compile warning',
 E_USER_ERROR      => 'user error',
 E_USER_WARNING    => 'user warning',
 E_USER_NOTICE     => 'user notice');
 $errortype[E_STRICT] = 'runtime notice';
// and instead of
// error_reporting(E_ALL | E_STRICT);
// one can use
error_reporting(E_ALL | (defined('E_STRICT')? E_STRICT : 0));
// to avoid that notice.


If you are using PHP as an Apache module, your default behavior may be to write PHP error messages to Apache's error log. This is because the error_log .ini directive may be set equal to "error_log" which is also the name of Apache's error log. I think this is intentional.
However, you can separate Apache errors from PHP errors if you wish by simply setting a different value for error_log. I write mine in the /var/log folder.


I keep seeing qualification lists for error types/error-nums as arrays; In user notes and in the manual itself. For example, in this manual entry's example, when trying to seperate behavior for the variable trace in the error report:
<?php //...
// set of errors for which a var trace will be saved
$user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE);
//and later...
if (in_array($errno, $user_errors)) {
//... ?>
I was under the impression that PHP error code values where bitwise flag values. Wouldn't bitwise masking be better? So I propose a slightly better way:
<?php //...
if ($errno & $user_errors) {
//... ?>
Or for those of you who don't like the idea of using an integer as the condition in an if statement:
if (($errno & $user_errors) > 0) {
I think that's much more efficient than using _yet another_ array() constuct and an in_array().
If I am wrong, and the E_* constants aren't supposed to be used in this fashion (ie, the constans aren't guaranteed to be bitwise, which would be odd since that's how they're setup in the php.ini file), then delete me. I just don't see why one should be using arrays when bitwise comparisons will work, considering the bitwise method should be MUCH more efficient.

petrov dot michael gmail com

I have found that on servers that enforce display_errors to be off it is very inconvenient to debug syntax errors since they cause fatal startup errors. I have used the following method to bypass this limitation:
The syntax error is inside the file "syntax.php", therefore I create a file "syntax.debug.php" with the following code:
The 5 line file is guaranteed to be free of errors, allowing PHP to execute the directives within it before including the file which previously caused fatal startup errors. Now those fatal startup errors become run time fatal errors.


As pointed out previously, PHP by default logs to the Apache ErrorLog.
Beware: the messages it logs do not conform to Apache's error log format (missing date and severity fields), so if you use an automated parser on your error logs, you'll want to redirect PHP's errors somewhere else with the error_log directive.


Although the root user writes to the files 'error_log' and 'access_log', the Apache user has to own the file referenced by 'error_log = filename' or no log entries will be written.
; From php.ini
; Log errors to specified file.
error_log = /usr/local/apache/logs/php.errors
[root@www logs]$ ls -l /usr/local/apache/logs/php.errors
-rw-r--r--    1 nobody   root          27K Jan 27 16:58 php.errors


A handy errorhandler class can be found at:
It has several enhancements (report layouts):
* prints the source code fragment where the error encountered,
* prints variable context around error source,
* suppresses error-messages, instead displays an arbitrary HTML or PHP page
* logging to multiple targets and autodetecting target logging
* error messages can be displayed in a separate browser window
* catching errors for runtime generated codes
* debugging variables.

Change Language

Follow Navioo On Twitter
.NET Functions
Apache-specific Functions
Alternative PHP Cache
Advanced PHP debugger
Array Functions
Aspell functions [deprecated]
BBCode Functions
BCMath Arbitrary Precision Mathematics Functions
PHP bytecode Compiler
Bzip2 Compression Functions
Calendar Functions
CCVS API Functions [deprecated]
Class/Object Functions
Classkit Functions
ClibPDF Functions [deprecated]
COM and .Net (Windows)
Crack Functions
Character Type Functions
Cybercash Payment Functions
Credit Mutuel CyberMUT functions
Cyrus IMAP administration Functions
Date and Time Functions
DB++ Functions
Database (dbm-style) Abstraction Layer Functions
dBase Functions
DBM Functions [deprecated]
dbx Functions
Direct IO Functions
Directory Functions
DOM Functions
DOM XML Functions
enchant Functions
Error Handling and Logging Functions
Exif Functions
Expect Functions
File Alteration Monitor Functions
Forms Data Format Functions
Fileinfo Functions
filePro Functions
Filesystem Functions
Filter Functions
Firebird/InterBase Functions
Firebird/Interbase Functions (PDO_FIREBIRD)
FriBiDi Functions
FrontBase Functions
FTP Functions
Function Handling Functions
GeoIP Functions
Gettext Functions
GMP Functions
gnupg Functions
Haru PDF Functions
hash Functions
Hyperwave Functions
Hyperwave API Functions
i18n Functions
IBM Functions (PDO_IBM)
iconv Functions
ID3 Functions
IIS Administration Functions
Image Functions
Imagick Image Library
Informix Functions
Informix Functions (PDO_INFORMIX)
Ingres II Functions
IRC Gateway Functions
PHP / Java Integration
JSON Functions
LDAP Functions
libxml Functions
Lotus Notes Functions
LZF Functions
Mail Functions
Mailparse Functions
Mathematical Functions
MaxDB PHP Extension
MCAL Functions
Mcrypt Encryption Functions
MCVE (Monetra) Payment Functions
Memcache Functions
Mhash Functions
Mimetype Functions
Ming functions for Flash
Miscellaneous Functions
mnoGoSearch Functions
Microsoft SQL Server Functions
Microsoft SQL Server and Sybase Functions (PDO_DBLIB)
Mohawk Software Session Handler Functions
mSQL Functions
Multibyte String Functions
muscat Functions
MySQL Functions
MySQL Functions (PDO_MYSQL)
MySQL Improved Extension
Ncurses Terminal Screen Control Functions
Network Functions
Newt Functions
NSAPI-specific Functions
Object Aggregation/Composition Functions
Object property and method call overloading
Oracle Functions
ODBC Functions (Unified)
ODBC and DB2 Functions (PDO_ODBC)
OpenAL Audio Bindings
OpenSSL Functions
Oracle Functions [deprecated]
Oracle Functions (PDO_OCI)
Output Control Functions
Ovrimos SQL Functions
Paradox File Access
Parsekit Functions
Process Control Functions
Regular Expression Functions (Perl-Compatible)
PDF Functions
PDO Functions
Phar archive stream and classes
PHP Options&Information
POSIX Functions
Regular Expression Functions (POSIX Extended)
PostgreSQL Functions
PostgreSQL Functions (PDO_PGSQL)
Printer Functions
Program Execution Functions
PostScript document creation
Pspell Functions
qtdom Functions
Rar Functions
GNU Readline
GNU Recode Functions
RPM Header Reading Functions
runkit Functions
SAM - Simple Asynchronous Messaging
Satellite CORBA client extension [deprecated]
SCA Functions
SDO Functions
SDO XML Data Access Service Functions
SDO Relational Data Access Service Functions
SESAM Database Functions
PostgreSQL Session Save Handler
Session Handling Functions
Shared Memory Functions
SimpleXML functions
SNMP Functions
SOAP Functions
Socket Functions
Standard PHP Library (SPL) Functions
SQLite Functions
SQLite Functions (PDO_SQLITE)
Secure Shell2 Functions
Statistics Functions
Stream Functions
String Functions
Subversion Functions
Shockwave Flash Functions
Swish Functions
Sybase Functions
TCP Wrappers Functions
Tidy Functions
Tokenizer Functions
Unicode Functions
URL Functions
Variable Handling Functions
Verisign Payflow Pro Functions
vpopmail Functions
W32api Functions
WDDX Functions
win32ps Functions
win32service Functions
xattr Functions
xdiff Functions
XML Parser Functions
XML-RPC Functions
XMLReader functions
XMLWriter Functions
XSL functions
XSLT Functions
YAZ Functions
YP/NIS Functions
Zip File Functions
Zlib Compression Functions
eXTReMe Tracker