(PHP 4, PHP 5, PHP 7)

syslogГенерирует сообщение для системного журнала


bool syslog ( int $priority , string $message )

Функция syslog() генерирует сообщение, которое направляется в системный журнал.

По поводу информации по установке пользовательского обработчика сообщений журнала см. Unix руководство в части syslog.conf (5). Дополнительную информацию по функционалу syslog можно получить с помощью man для syslog (3) на Unix машинах.

Список параметров


Параметр priority - это комбинация установки и уровня. Возможными значениями являются:

syslog() приоритеты (по убыванию)
Константа Описание
LOG_EMERG система непригодна
LOG_ALERT необходимы незамедлительные меры
LOG_CRIT критические условия
LOG_ERR условия ошибки
LOG_WARNING условия предупреждения
LOG_NOTICE нормальные, но значительные условия
LOG_INFO информационное сообщение
LOG_DEBUG сообщение отладки

Параметр message

Отсылаемое сообщение, исключая то, что два символа %m будут заменены строкой сообщения об ошибке (strerror), соответствующей текущему значению errno.

Возвращаемые значения

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.


Пример #1 Пример использования syslog()

// открыть syslog, включить в сообщение ID процесса, также отправить
// сообщение, и использовать определенный пользователем
// механизм журналирования
openlog("myScriptLog"LOG_PID LOG_PERRORLOG_LOCAL0);

// некий код

if (authorized_client()) {
// исполнение любого кода
} else {
// неавторизованный клиент!
    // отправить сообщение журнала о попытке
$access date("Y/m/d H:i:s");
syslog(LOG_WARNING"Неавторизованный клиент: $access {$_SERVER['REMOTE_ADDR']} ({$_SERVER['HTTP_USER_AGENT']})");



На Windows NT, служба syslog эмулируется используя Журнал Событий.


Использование LOG_LOCAL0 через LOG_LOCAL7 для параметра facility в функции openlog() недоступно в Windows.

Смотрите также

  • openlog() - Открывает соединение к системному журналу
  • closelog() - Завершает соединение с системным журналом


In Windows NT, use the following values of priority:
1 = error,
6 = info
1999-09-08 06:54:13
For the-header-file-enabled:

man 3 syslog defines the priorities, but not the integer values. For that you'll need to read your system header file.

Let's suppose I want to log an informational message in the mail log (which happens to be true). The man page tells me I want LOG_MAIL|LOG_INFO. So I look in /usr/include/sys/syslog.h and find (this happens to be Linux, your system could be different):

#define LOG_INFO        6       /* informational */
#define LOG_MAIL        (2<<3)  /* mail system */

2<<3 means shift 3 bits left, which means multiply by 8. So I want 2*8 + 6 = 22. syslog(22,"this message will appear in the mail log"); And indeed it does.
2000-02-17 02:51:53
Example of where to look for syslog's output:   /var/log/httpd/access_log
(on Red Hat Linux Secure Server v6.2).
2000-12-20 15:09:26
With FreeBSD I can use: syslog(LOG_INFO,"test");

BSD/OS does not support this, I had to use the literal values for the priority (158:
2001-01-22 08:11:44
To set up a custom log file via the syslog daemon (FreeBSD in this case)...

Add to /etc/syslog.conf a line that says all errors from the httpd process are to go to a file called (for example) /var/log/httpd-php.log

*.*   {tab}   /var/log/httpd-php.log

Note the tab, being a tab character! Next create a blank file to be written to. I'm sure there are 1e+6 ways to do this, but I choose

# cat > httpd-php.log << EOF

Finally find your syslog daemon and send it a sighup to inform it of the change:

# ps ax | grep syslogd
  133  ??  Ss     0:07.23 syslogd -s
# kill -1 133

Et voila! Php syslog calls will now arrive in /var/log/httpd-php.log
2002-01-29 18:08:41
This *does* actually goto the system log as configured in /etc/syslog.conf (such as /var/log/messages), it doesn't goto Apache's ErrorLog (such as /var/log/httpd/error_log). At least under my Debian Potato with Apache 1.3.23.

Use error_log() to be sure it gets into Apache's ErrorLog.
2002-03-31 11:32:42
The message string sent to the log file is limited to 500 characters.
2003-07-28 20:05:58
This work for me, to redirect  logs to a separate syslog file

put this line in your /etc/syslog.conf :

local0.debug   /var/log/php.log

Then restart syslogd:

/etc/init.d/syslog restart

php example:


$data date("Y/m/d H:i:s");
syslog(LOG_DEBUG,"Messagge: $data");

2003-11-06 13:00:31
I had a problem trying to issue a syslog message with IIS 5.1 under Windows XP. The function call seemed to succeed, but the event viewer showed that no entry was made.
Finally I found out that the user account used for the webserver (IUSR_<Computername>) did not have enough permissions to issue syslog alerts. I changed this by adding this user to the Users group instead of only Guest.
2004-04-23 09:27:15
Be aware when using syslog() that if you set the timezone of environment to be something other than the standard, syslog() may log the time to the log(s) with the wrong time zone information. For example:



syslog(LOG_INFO'UTC Log line');

syslog(LOG_INFO'US/Pacific Log line');



Viewing the /usr/log/messages log will display these two lines:

Apr 11 01:25:39 hostname mylog[1400]: UTC Log line
Apr 10 18:25:39 hostname mylog[1400]: US/Pacific Log line

2007-04-10 21:32:04
If you are using syslog-ng and want errors send to syslog then use ini setting "error_log = syslog" and add something like the following to your syslog-ng.conf:

destination php { file("/var/log/php.log" owner(root) group(devel) perm(0620)); };
log { source(src); filter(f_php); destination(php); };
2007-04-13 08:49:15
If anyone is wondering why their log messages are appearing in multiple log files, here is one answer applying to *nix systems:

If your syslog.conf looks like this (assuming you use LOG_LOCAL0 for web app logging) :    /var/log/web/info.log

This will collect *all* messages of LOG_INFO level and higher, i.e everything except debug messages

Try this instead to ensure that only messages of the named log level go into the relevant log file:

local0.=info    /var/log/web/info.log

Additionally, you may like to add this to ensure your messages don't end up in generic log files like "messages"  "all" "syslog" and "debug":

local0.none    /var/log/messages
local0.none    /var/log/debug

saves disk space among other things - more at "man syslog.conf"
2007-12-02 22:26:35
A word of warning; if you use openlog() to ready syslog() and your Apache threads accept multiple requests, you *must* call closelog() if Apache's error log is configured to write to syslog.  Failure to do so will cause Apache's error log to write to whatever facility/ident was used in openlog.

Example, in httpd.conf you have:

ErrorLog syslog:local7

and in php you do:

syslog("My syslog message");

From here on out, this Apache thread will write ErrorLog to local0 and under the process name "myprogram" and not httpd!  Calling closelog() will fix this.
2010-05-11 16:57:16
For those who want to simultaneously write to multiple syslog facilities : 

syslog(LOG_INFO|LOG_LOCAL0, "message for local0");
syslog(LOG_INFO|LOG_LOCAL1, "message for local1");
2015-05-11 07:34:02
The documentation is incorrect when it says "Priorities (in descending order)", as the table that follows is actually in **ascending** order.

For example my output says:

An important difference, that caused me some pain!
2015-12-21 13:48:56
This function sends messages in BSD Syslog RFC 3164 format (

To see the raw messages being sent by PHP to the logging socket, first stop your syslog/rsylsog/ng-syslog service, then listen to the logging socket with the netcat-openbsd package:

nc -U -l /dev/log

Now, log something from PHP:


You will see the rfc3164 output from netcat:

<142>Oct 24 14:32:51 php: Test from PHP
2018-10-24 21:43:52
This one had me going for a while when using LOG_ constants in another object, when developing on Windows, but deploying on Linux.

Windows evaluates some of the LOG_ constants to the same value, while LINUX does not.

The 8 constants and their differences on the platforms to be aware of:

Linux has these values as:

While on Windows, you have:

So if you're setting LOG_WARNING in your code, Linux will use 4 as the priority while Windows will use 5.

This is not a bug in PHP on either platform, but a difference in the system header files that PHP compiles with.  Not really anything you can do, but be aware if you're wondering why your messages log at different priorities depending on the platform, this could be why.
2019-02-09 06:39:21
Syslog autodetects newline control characters and therefore splits the message by multiple lines. To prevent this behavior in PHP 7.3+ you can use undocumented (at this moment) ini setting:



# more info here:
2020-07-02 07:45:16

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