Retrieve the type map:
typemap_get -i 15

response:
<response command="typemap_get" transaction_id="15"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <map name="bool" type="bool" xsi:type="xsd:boolean"></map>
  <map name="int" type="int" xsi:type="xsd:decimal"></map>
  <map name="float" type="float" xsi:type="xsd:double"></map>
  <map name="string" type="string" xsi:type="xsd:string"></map>
  <map name="null" type="null"></map>
  <map name="array" type="hash"></map>
  <map name="object" type="object"></map>
  <map name="resource" type="resource"></map>
</response>