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error_reporting> <error_get_last
Last updated: Fri, 16 May 2008

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error_log

(PHP 4, PHP 5)

error_log — Send an error message somewhere

Description

bool error_log ( string $message [, int $message_type [, string $destination [, string $extra_headers ]]] )

Sends an error message to the web server's error log, a TCP port or to a file.

Parameters

message

The error message that should be logged.

message_type

Says where the error should go. The possible message types are as follows:

error_log() log types
0 message is sent to PHP's system logger, using the Operating System's system logging mechanism or a file, depending on what the error_log configuration directive is set to. This is the default option.
1 message is sent by email to the address in the destination parameter. This is the only message type where the fourth parameter, extra_headers is used.
2 No longer an option.
3 message is appended to the file destination . A newline is not automatically added to the end of the message string.

destination

The destination. Its meaning depends on the message_type parameter as described above.

extra_headers

The extra headers. It's used when the message_type parameter is set to 1. This message type uses the same internal function as mail() does.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 error_log() examples

<?php
// Send notification through the server log if we can not
// connect to the database.
if (!Ora_Logon($username$password)) {
    
error_log("Oracle database not available!"0);
}

// Notify administrator by email if we run out of FOO
if (!($foo allocate_new_foo())) {
    
error_log("Big trouble, we're all out of FOOs!"1,
               
"operator@example.com");
}

// another way to call error_log():
error_log("You messed up!"3"/var/tmp/my-errors.log");
?>



error_reporting> <error_get_last
Last updated: Fri, 16 May 2008
 
add a note add a note User Contributed Notes
error_log
i dot buttinoni at intandtel dot com
16-Feb-2008 11:32
Be carefull. Unexpected PHP dies when 2GByte of file log reached (on systems having upper file size limit).
A work aorund is rotate logs :)
SJL
01-Jan-2008 02:16
"It appears that the system log = stderr if you are running PHP from the command line"

Actually, it seems that PHP logs to stderr if it can't write to the log file. Command line PHP falls back to stderr because the log file is (usually) only writable by the webserver.
larry.kooper at gmail dot com
11-Oct-2007 11:00
On a Mac running OS X, for the error logging to work I needed to put this in my php.ini:
error_log = /tmp/php_errors.log
Attempting to put the log in other locations did not work, probably due to permission issues.
stepheneliotdewey at GmailDotCom
27-Jun-2007 02:05
Note that since typical email is unencrypted, sending data about your errors over email using this function could be considered a security risk. How much of a risk it is depends on how much and what type of information you are sending, but the mere act of sending an email when something happens (even if it cannot be read) could itself imply to a sophisticated hacker observing your site over time that they have managed to cause an error.

Of course, security through obscurity is the weakest kind of security, as most open source supporters will agree. This is just something that you should keep in mind.

And of course, whatever you do, make sure that such emails don't contain sensitive user data.
frank at booksku dot com
02-Nov-2006 11:28
Beware!  If multiple scripts share the same log file, but run as different users, whichever script logs an error first owns the file, and calls to error_log() run as a different user will fail *silently*!

Nothing more frustrating than trying to figure out why all your error_log calls aren't actually writing, than to find it was due to a *silent* permission denied error!
p dot lhonorey at nospam-laposte dot net
28-Aug-2006 11:33
Hi !

Another trick to post "HTML" mail body. Just add "Content-Type: text/html; charset=ISO-8859-1" into extra_header string. Of course you can set charset according to your country or Env or content.

EG: Error_log("<html><h2>stuff</h2></html>",1,"eat@joe.com","subject  :lunch\nContent-Type: text/html; charset=ISO-8859-1");

Enjoy !
marques at displague dot com
26-Aug-2005 09:52
Beware the size of your custom error_log!

Once it exceeds 2GB the function errors, ending your script at the error_log() line.  I'm sure this differs from OS to OS, but I have seen it die writing to ext2 under modern Linux systems.
mac at codegreene dot com
08-Aug-2005 05:33
When outputting to syslog, it uses the syslog() function, which limits its output to 500 characters. We have been able to send multi-line output to the log, but newlines appear to be replaced with a space in the output, and output is cut off at 500 characters.

A simple workaround for long, multi-line output is something like this:

$errlines = explode("\n",$errmsg);
foreach ($errlines as $txt) { error_log($txt); }
php at kennel17 dot NOSPAM dot co dot uk
25-Jul-2005 10:04
It appears that the system log = stderr if you are running PHP from the command line, and that often stderr = stdout.  This means that if you are using a custom error to both display the error and log it to syslog, then a command-line user will see the same error reported twice.
kazezb at nospam dot carleton dot edu
21-Jul-2005 06:39
It appears that error_log() only logs the first line of multi-line log messages. To log a multi-line message, either log each line individually or write the message to another file.
franz at fholzinger dot com
20-Apr-2005 05:21
In the case of missing your entries in the error_log file:
When you use error_log in a script that does not produce any output, which means that you cannot see anything during the execution of the script, and when you wonder why there are no error_log entries produced in your error_log file, the reasons can be:
- you did not configure error_log output in php.ini
- the script has a syntax error and did therefore not execute
28-Mar-2003 10:14
when using error_log to send email, not all elements of an extra_headers string are handled the same way.  "From: " and "Reply-To: " header values will replace the default header values. "Subject: " header values won't: they are *added* to the mail header but don't replace the default, leading to mail messages with two Subject fields.

<?php

error_log
("sometext", 1, "zigzag@my.domain",
 
"Subject: Foo\nFrom: Rizzlas@my.domain\n");

?>

---------------%<-----------------------
To: zigzag@my.domain
Envelope-to: zigzag@my.domain
Date: Fri, 28 Mar 2003 13:29:02 -0500
From: Rizzlas@my.domain
Subject: PHP error_log message
Subject: Foo
Delivery-date: Fri, 28 Mar 2003 13:29:03 -0500

sometext
---------------%<---------------------

quoth the docs: "This message type uses the same internal function as mail() does." 

mail() will also fail to set a Subject field based on extra_header data - instead it takes a seperate argument to specify a "Subject: " string.

php v.4.2.3, SunOS 5.8
dan at mojavelinux dot com
01-Feb-2003 07:46
I find it very suprising that there are no PHP constants (or references to them if they exist) for the log types.  I would expect

SYSTEM_LOG = 0
TCP_LOG = 1
FILE_LOG = 2
MAIL_LOG = 3

or something to that nature.  Are we going to see this in any future versions?  Seems very silly to use integers here when they could easily be changed or confused.

error_reporting> <error_get_last
Last updated: Fri, 16 May 2008
 
 
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