<@ISNULLOBJECT OBJECT=variable [SCOPE=scope]>
The <@ISNULLOBJECT> meta tag tests whether a variable is a null object. This tag returns 1 if the specified variable is an object variable and is null. The OBJECT attribute is required and specifies the name of an object variable. The SCOPE is optional, and specifies the scope of the object variable.
If a Tango class file returned an object variable, you could use <@ISNULLOBJECT> to check whether this object was null before calling methods on it. Because the type of the returned variable from the Tango class file is "object", an object variable is always returned; however, if some error occurs within the Tango class file such that the particular object is not accessible, a null object is returned. This meta tag is useful for checking for such errors.
<@CALLMETHOD>
<@CREATEOBJECT>
<@NUMOBJECTS>
<@OBJECTAT>
<@OBJECTS></@OBJECTS>