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    Hello,<br>
    <br>
    $var(...) cannot be deleted. Its implementation relies on startup
    replacement of the name with a pointer in memory, at runtime being
    used only the pointer (for speed considerations). You should use
    $avp() if you want to deal with $null.<br>
    <br>
    For the second, it depends on transformation, afaik, most
    transformations don't return null, but empty string (at least the
    string transformations). If you implement a new one and want to
    return $null, the value must have the flag PV_VAL_NULL set, like:
    val->flags  |= PV_VAL_NULL<br>
    <br>
    Cheers,<br>
    Daniel<br>
    <br>
    <div class="moz-cite-prefix">On 05/01/15 13:36, Luis Azedo wrote:<br>
    </div>
    <blockquote
cite="mid:6FFC6465A51B5B4C80DD111E16112FD1C40692@mbx022-w1-ca-4.exch022.domain.local"
      type="cite">
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      <div style="direction: ltr;font-family: Tahoma;color:
        #000000;font-size: 10pt;">HI Daniel,
        <div><br>
        </div>
        <div>thanks, so in the first case instead of assigning the value
          to the $var(x) can i delete the $var(x) so that comparison
          works ?</div>
        <div><br>
        </div>
        <div>in the second case (returned value from transform) what
          value should i compare against to check if returned value was
          null ?</div>
        <div><br>
          <div style="font-family: Times New Roman; color: #000000;
            font-size: 16px">
            <hr tabindex="-1">
            <div id="divRpF769188" style="direction: ltr;"><font
                color="#000000" face="Tahoma" size="2"><b>From:</b>
                sr-dev [<a class="moz-txt-link-abbreviated" href="mailto:sr-dev-bounces@lists.sip-router.org">sr-dev-bounces@lists.sip-router.org</a>] on behalf
                of Daniel-Constantin Mierla [<a class="moz-txt-link-abbreviated" href="mailto:miconda@gmail.com">miconda@gmail.com</a>]<br>
                <b>Sent:</b> Monday, January 05, 2015 3:51 AM<br>
                <b>To:</b> Kamailio (SER) - Development Mailing List<br>
                <b>Subject:</b> Re: [sr-dev] need help understanding
                $null<br>
              </font><br>
            </div>
            <div>Hello,<br>
              <br>
              $var(...) cannot be null by design, setting it to $null
              makes it 0.<br>
              <br>
              $null is more for variables that don't exist, e.g., you
              don't have the $avp(x), then it is null if you compare it.<br>
              <br>
              Cheers,<br>
              Daniel<br>
              <br>
              <div class="moz-cite-prefix">On 04/01/15 12:35, Luis Azedo
                wrote:<br>
              </div>
              <blockquote type="cite">
                <style type="text/css" id="owaParaStyle"></style>
                <div style="direction:ltr; font-family:Tahoma;
                  color:#000000; font-size:10pt">Hi Daniel,
                  <div><br>
                  </div>
                  <div>can you help on this ?</div>
                  <div><br>
                  </div>
                  <div>Thank you<br>
                    <div style="font-family:Times New Roman;
                      color:#000000; font-size:16px">
                      <hr tabindex="-1">
                      <div id="divRpF307304" style="direction:ltr"><font
                          color="#000000" face="Tahoma" size="2"><b>From:</b>
                          sr-dev [<a moz-do-not-send="true"
                            class="moz-txt-link-abbreviated"
                            href="mailto:sr-dev-bounces@lists.sip-router.org"
                            target="_blank">sr-dev-bounces@lists.sip-router.org</a>]
                          on behalf of Luis Azedo [<a
                            moz-do-not-send="true"
                            class="moz-txt-link-abbreviated"
                            href="mailto:luis@2600hz.com"
                            target="_blank">luis@2600hz.com</a>]<br>
                          <b>Sent:</b> Wednesday, December 31, 2014 4:19
                          AM<br>
                          <b>To:</b> <a moz-do-not-send="true"
                            class="moz-txt-link-abbreviated"
                            href="mailto:sr-dev@lists.sip-router.org"
                            target="_blank">
                            sr-dev@lists.sip-router.org</a><br>
                          <b>Subject:</b> [sr-dev] need help
                          understanding $null<br>
                        </font><br>
                      </div>
                      <div>
                        <div style="direction:ltr; font-family:Tahoma;
                          color:#000000; font-size:10pt">Hi,
                          <div><br>
                          </div>
                          <div>if we return val.flags = PV_VAL_NULL,
                            does the == $null comparison work ?</div>
                          <div><br>
                          </div>
                          <div>script example</div>
                          <div><br>
                          </div>
                          <div>my_function("some param","$var(result)");</div>
                          <div>if( $var(result<span
                              style="font-size:10pt">) == $null {</span></div>
                          <div><span style="font-size:10pt">  do
                              something</span></div>
                          <div><span style="font-size:10pt">}</span></div>
                          <div>
                            <div><span style="font-size:10pt">in code
                                => dst_pv->setf(msg,
                                &dst_pv->pvp, (int)EQ_T,
                                &dst_val);</span></div>
                          </div>
                          <div>
                            <div><span style="font-size:10pt"> should
                                the comparison work if we set </span>dst_val<span
                                style="font-size:10pt">.flags =
                                PV_VAL_NULL ?</span></div>
                          </div>
                          <div><span style="font-size:10pt"><br>
                            </span></div>
                          <div><br>
                          </div>
                          <div>if(
                            $(myPvar{my.mytransform,transformParameter})
                            == $null) {</div>
                          <div>  ....</div>
                          <div>}</div>
                          <div>should this work if the transform
                            returns <span style="font-size:10pt">val.flags
                              = PV_VAL_NULL ?</span></div>
                          <div><span style="font-size:10pt"><br>
                            </span></div>
                          <div><span style="font-size:10pt"><br>
                            </span></div>
                          <div><span style="font-size:10pt">thank you</span></div>
                          <div><span style="font-size:10pt"><br>
                            </span></div>
                          <div><br>
                          </div>
                          <div><br>
                          </div>
                          <div><br>
                          </div>
                          <div><br>
                          </div>
                        </div>
                      </div>
                    </div>
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                <br>
                <pre>_______________________________________________
sr-dev mailing list
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:sr-dev@lists.sip-router.org" target="_blank">sr-dev@lists.sip-router.org</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev" target="_blank">http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev</a>
</pre>
              </blockquote>
              <br>
              <pre class="moz-signature" cols="72">-- 
Daniel-Constantin Mierla
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://twitter.com/#%21/miconda" target="_blank">http://twitter.com/#!/miconda</a> - <a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.linkedin.com/in/miconda" target="_blank">http://www.linkedin.com/in/miconda</a></pre>
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    </blockquote>
    <br>
    <pre class="moz-signature" cols="72">-- 
Daniel-Constantin Mierla
<a class="moz-txt-link-freetext" href="http://twitter.com/#!/miconda">http://twitter.com/#!/miconda</a> - <a class="moz-txt-link-freetext" href="http://www.linkedin.com/in/miconda">http://www.linkedin.com/in/miconda</a></pre>
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