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<appref>
  <header>
    <copyright>
      <year>1996</year><year>2009</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
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      retrieved online at http://www.erlang.org/.
    
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      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.
    
    </legalnotice>

    <title>sasl</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
  </header>
  <app>sasl</app>
  <appsummary>The SASL Application</appsummary>
  <description>
    <p>This section describes the SASL (System Architecture Support Libraries)
      application which provides the following services:</p>
    <list type="bulleted">
      <item><c>alarm_handler</c></item>
      <item><c>overload</c></item>
      <item><c>rb</c></item>
      <item><c>release_handler</c></item>
      <item><c>systools</c></item>
    </list>
    <p>The SASL application also includes <c>error_logger</c> event
      handlers for formatting SASL error and crash reports.</p>

    <note>
       <p>The SASL application in OTP has nothing to do with
          "Simple Authentication and Security Layer" (RFC 4422).</p>
    </note>

  </description>

  <section>
    <title>Error Logger Event Handlers</title>
    <p>The following error logger event handlers are defined in
      the SASL application.</p>
    <taglist>
      <tag><c>sasl_report_tty_h</c></tag>
      <item>
        <p>Formats and writes <em>supervisor reports</em>, <em>crash reports</em> and <em>progress reports</em> to <c>stdio</c>.</p>
      </item>
      <tag><c>sasl_report_file_h</c></tag>
      <item>
        <p>Formats and writes <em>supervisor reports</em>, <em>crash report</em> and <em>progress report</em> to a single file.</p>
      </item>
      <tag><c>error_logger_mf_h</c></tag>
      <item>
        <p>This error logger writes <em>all</em> events sent to
          the error logger to disk. It installs the <c>log_mf_h</c>
          event handler in the <c>error_logger</c> process.</p>
      </item>
    </taglist>
  </section>

  <section>
    <title>Configuration</title>
    <p>The following configuration parameters are defined for the SASL
      application. See <c>app(4)</c> for more information about
      configuration parameters:</p>
    <taglist>
      <tag><c><![CDATA[sasl_error_logger = Value <optional>]]></c></tag>
      <item>
        <p><c>Value</c> is one of:</p>
        <taglist>
          <tag><c>tty</c></tag>
          <item>Installs <c>sasl_report_tty_h</c> in the error logger.
           This is the default option.</item>
          <tag><c>{file,FileName}</c></tag>
          <item>Installs <c>sasl_report_file_h</c> in the error logger.
           This makes all reports go to the file <c>FileName</c>.
          <c>FileName</c> is a string.</item>
          <tag><c>false</c></tag>
          <item>
            <p>No SASL error logger handler is installed.</p>
          </item>
        </taglist>
      </item>
      <tag><c><![CDATA[errlog_type = error | progress | all <optional>]]></c></tag>
      <item>
        <p>Restricts the error logging performed by the specified
          <c>sasl_error_logger</c> to error reports, progress reports,
          or both. Default is <c>all</c>.</p>
      </item>
      <tag><c><![CDATA[error_logger_mf_dir = string() | false<optional>]]></c></tag>
      <item>
        <p>Specifies in which directory the files are stored. If this
          parameter is undefined or <c>false</c>,
          the <c>error_logger_mf_h</c> is not installed.</p>
      </item>
      <tag><c><![CDATA[error_logger_mf_maxbytes = integer() <optional>]]></c></tag>
      <item>
        <p>Specifies how large each individual file can be. If this
          parameter is undefined, the <c>error_logger_mf_h</c> is not
          installed.</p>
      </item>
      <tag><c><![CDATA[error_logger_mf_maxfiles = 0<integer()<256 <optional>]]></c></tag>
      <item>
        <p>Specifies how many files are used. If this parameter is
          undefined, the <c>error_logger_mf_h</c> is not installed.</p>
      </item>
      <tag><c><![CDATA[overload_max_intensity = float() > 0 <optional>]]></c></tag>
      <item>
        <p>Specifies the maximum intensity for <c>overload</c>. Default
          is <c>0.8</c>.</p>
      </item>
      <tag><c><![CDATA[overload_weight = float() > 0 <optional>]]></c></tag>
      <item>
        <p>Specifies the <c>overload</c> weight. Default is <c>0.1</c>.</p>
      </item>
      <tag><c><![CDATA[start_prg = string() <optional>]]></c></tag>
      <item>
        <p>Specifies which program should be used when restarting
          the system. Default is <c>$OTP_ROOT/bin/start</c>.</p>
      </item>
      <tag><c><![CDATA[masters = [atom()] <optional>]]></c></tag>
      <item>
        <p>Specifies which nodes this node uses to read/write release
          information. This parameter is ignored if
          the <c>client_directory</c> parameter is not set.</p>
      </item>
      <tag><c><![CDATA[client_directory = string() <optional>]]></c></tag>
      <item>
        <p>This parameter specifies the client directory at the master
          nodes. Refer to Release Handling in <em>OTP Design Principles</em> for more information.  This parameter is
          ignored if the <c>masters</c> parameter is not set.</p>
      </item>
      <tag><c><![CDATA[static_emulator = true | false <optional>]]></c></tag>
      <item>
        <p>Indicates if the Erlang emulator is statically installed. A
          node with a static emulator cannot switch dynamically to a
          new emulator as the executable files are written into memory
          statically.  This parameter is ignored if the <c>masters</c>
          and <c>client_directory</c> parameters are not set.</p>
      </item>
      <tag><c><![CDATA[releases_dir = string() <optional>]]></c></tag>
      <item>
        <p>Indicates where the <c>releases</c> directory is located.
          The release handler writes all its files to this directory.
          If this parameter is not set, the OS environment parameter
          <c>RELDIR</c> is used. By default, this is
          <c>$OTP_ROOT/releases</c>.</p>
      </item>
      <tag><c><![CDATA[utc_log = true | false <optional>]]></c></tag>
      <item>
        <p>If set to <c>true</c>, all dates in textual log outputs are
          displayed in Universal Coordinated Time with the string
          <c>UTC</c> appended.</p>
      </item>
    </taglist>
  </section>

  <section>
    <title>See Also</title>
    <p><seealso marker="alarm_handler">alarm_handler(3)</seealso>,
      error_logger(3),
      log_mf_h(3),
      <seealso marker="overload">overload(3)</seealso>,
      <seealso marker="rb">rb(3)</seealso>,
      <seealso marker="release_handler">release_handler(3)</seealso>,
      <seealso marker="systools">systools(3)</seealso></p>
  </section>
</appref>

