- var_dump: documentation ( source)
<?php
$xml = <<<XML
<DataSet>
<xs:schema id="OutDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<xs:element name="OutDataSet" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
<xs:complexType>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="BuscaSMS">
<xs:complexType>
<xs:sequence>
<xs:element name="seunum" type="xs:string" minOccurs="0" />
<xs:element name="celular" type="xs:string" minOccurs="0" />
<xs:element name="mensagem" type="xs:string" minOccurs="0" />
<xs:element name="status" type="xs:string" minOccurs="0" />
<xs:element name="datarec" type="xs:dateTime" minOccurs="0" />
<xs:element name="dataenv" type="xs:dateTime" minOccurs="0" />
<xs:element name="datastatus" type="xs:dateTime" minOccurs="0" />
<xs:element name="op" type="xs:short" minOccurs="0" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
</xs:element>
</xs:schema>
<diffgr:diffgram xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" xmlns:diffgr="urn:schemas-microsoft-com:xml-diffgram-v1">
<OutDataSet xmlns="">
<BuscaSMS diffgr:id="BuscaSMS0" msdata:rowOrder="3">
<seunum>999999999</seunum>
<celular>9999999999</celular>
<mensagem>obrigado</mensagem>
<status>MO</status>
<datarec>2018-02-01T13:30:51.547-02:00</datarec>
<dataenv>2018-02-01T13:30:52.773-02:00</dataenv>
<datastatus>2018-02-01T13:30:52.773-02:00</datastatus>
<op>5</op>
</BuscaSMS>
<BuscaSMS diffgr:id="BuscaSMS1" msdata:rowOrder="4">
<seunum>99999999999</seunum>
<celular>9999999999</celular>
<mensagem>Obrigado.</mensagem>
<status>MO</status>
<datarec>2018-02-01T13:37:17.18-02:00</datarec>
<dataenv>2018-02-01T13:37:20.807-02:00</dataenv>
<datastatus>2018-02-01T13:37:20.807-02:00</datastatus>
<op>5</op>
</BuscaSMS>
</OutDataSet>
</diffgr:diffgram>
</DataSet>
XML;
$dom = new \DOMDocument();
$dom->loadXML($xml);
foreach($dom->getElementsByTagName('BuscaSMS') as $buscaSMS)
{
var_dump($buscaSMS);
}