# Adding diagnostic messages

Plug-in specific warning and error messages can be added to the set of messages supplied by the DITA-OT. These messages can then be used by any XSLT override.

`dita.xsl.messages`
  Add new messages to diagnostic message file.

## Example

To add your own messages, create the new messages in an XML file such as myMessages.xml:

    <dummy>
      <!-- See resource/messages.xml for the details. -->
      <message id="DOTXmy-msg-numW" type="WARN">
        <reason>Message text</reason>
        <response>How to resolve</response>
      </message>
    </dummy>

There are three components to the message ID:

1. The prefix DOTX is used by all DITA-OT XSLT transforms, and must be part of the ID.
2. This is followed by the message number ("my-msg-num" in the sample above).
3. Finally, a letter corresponds to the severity. This should be one of:
   - I = Informational, used with type="INFO"
   - W = Warning, used with type="WARN"
   - E = Error, used with type="ERROR"
   - F = Fatal, used with type="FATAL"

Once the message file is defined, it is incorporated with this extension:

    <plugin id="com.example.newmsg">
      <feature extension="dita.xsl.messages" file="myMessages.xml"/>
    </plugin>

XSLT modules can then generate the message using the following call:

    <xsl:call-template name="output-message">
      <xsl:with-param name="msgnum">my-msg-num</xsl:with-param>
      <xsl:with-param name="msgsev">W</xsl:with-param>
    </xsl:call-template>

Parent topic: Creating DITA-OT plug-ins