This method takes one parameter, the name of a method implemented by the XML-RPC server.

It returns an array of possible signatures for this method. A signature is an array of types. The first of these types is the return type of the method, the rest are parameters.

Multiple signatures (i.e. overloading) are permitted: this is the reason that an array of signatures are returned by this method.

Signatures themselves are restricted to the top level parameters expected by a method. For instance if a method expects one array of structs as a parameter, and it returns a string, its signature is simply "string, array". If it expects three integers, its signature is "string, int, int, int".

For parameters that can be of more than one type, the "undefined" string is supported.

If no signature is defined for the method, a not-array value is returned. Therefore this is the way to test for a non-signature, if $resp below is the response object from a method call to system.methodSignature:

$v = $resp->value();
if ($v->kindOf() != "array") {
  // then the method did not have a signature defined
}

See the introspect.php demo included in this distribution for an example of using this method.