openlog

    (PHP 4, PHP 5, PHP 7, PHP 8)

    openlog — Open connection to system logger

    Description

    openlog(string $prefix, int $flags, int $facility): true

    openlog() opens a connection to the system logger for a program.

    The use of openlog() is optional. It will automatically be called by syslog() if necessary, in which case prefix will default to false.

    Parameters

    prefix

    The string prefix is added to each message.

    flags

    The flags argument is used to indicate what logging options will be used when generating a log message.

    openlog() Options
    Constant Description
    LOG_CONS if there is an error while sending data to the system logger, write directly to the system console
    LOG_NDELAY open the connection to the logger immediately
    LOG_ODELAY (default) delay opening the connection until the first message is logged
    LOG_PERROR print log message also to standard error
    LOG_PID include PID with each message
    You can use one or more of these options. When using multiple options you need to OR them, i.e. to open the connection immediately, write to the console and include the PID in each message, you will use: LOG_CONS | LOG_NDELAY | LOG_PID

    facility

    The facility argument is used to specify what type of program is logging the message. This allows you to specify (in your machine's syslog configuration) how messages coming from different facilities will be handled.

    openlog() Facilities
    Constant Description
    LOG_AUTH security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
    LOG_AUTHPRIV security/authorization messages (private)
    LOG_CRON clock daemon (cron and at)
    LOG_DAEMON other system daemons
    LOG_KERN kernel messages
    LOG_LOCAL0 ... LOG_LOCAL7 reserved for local use, these are not available in Windows
    LOG_LPR line printer subsystem
    LOG_MAIL mail subsystem
    LOG_NEWS USENET news subsystem
    LOG_SYSLOG messages generated internally by syslogd
    LOG_USER generic user-level messages
    LOG_UUCP UUCP subsystem

    Note:

    LOG_USER is the only valid log type under Windows operating systems

    Return Values

    Always returns true.

    Changelog

    Version Description
    8.2.0 The function now always returns true. Previously it returned false on failure.

    See Also

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    User Contributed Notes 2 notes

    up
    1
    sam dot wankaner at gmail dot com
    9 years ago
    In second parameter int $option, PI means Process ID (PID).
    That is the unique number given to that process. For eg [30326]
    up
    1
    Nimja
    11 years ago
    To those curious; switching between different facilities is NOT an issue. There is no apparent memory overhead (nor slowdown) by calling openlog multiple(12 * 10000) times.

    Shown by this example:

    <?php
    $facilities     = array(
    LOG_AUTH,
    LOG_AUTHPRIV,
    LOG_CRON,
    LOG_DAEMON,
    LOG_KERN,
    LOG_LOCAL0,
    LOG_LPR,
    LOG_MAIL,
    LOG_NEWS,
    LOG_SYSLOG,
    LOG_USER,
    LOG_UUCP,
    );

    for (    $i = 0; $i < 10000; $i++) {
    foreach (    $facilities as $facility) {
    openlog('test', LOG_PID, $facility);
    syslog(LOG_ERR, "This is a test: " . memory_get_usage(true));
    }
    }
    ?>
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