Inherited description: XMLIGNORENULL allows the programmer to override the default XML handling
of empty strings for properties of type %String. By default (XMLIGNORENULL = 0),
empty strings in the XML input are stored as $c(0) and $c(0) is written to XML
as an empty tag. A missing tag in the XML input is always stored as "" and
"" is always output to XML as no tag.
If XMLIGNORENULL is set = 1, then both missing tags in the XML and empty
strings are input as "", and both "" and $c(0) are output as empty tags
If XMLIGNORENULL is set = "inputonly", then both missing tags in the XML and empty
strings are input as "". Output of "" and $c(0) are for XMLIGNORENULL = 0:
$c(0) is output as an empty tag (i.e. <tag></tag>) and "" is output as no tag.
If XMLIGNORENULL = "runtime" (runtime is not case sensitive), then the behavior
of XMLIGNORENULL is determined by the format parameter of XMLExport, XMLImport
and %XML.Reader.OpenFile. The default behavior for XMLIGNORENULL="runtime is
the same as XMLIGNORENULL=0. Adding "ignorenull" to the format argument changes
the behavior to that of XMLIGNORENULL=1. "ignorenull" shoud be separated by a comma
from literal/encoded part of the format. Example values for format are "", ",ignorenull",
"literal,ignorenull" and "encoded,ignorenull".
Note that "inputonly" is equivalent to using ,ignorenull for XMLExport and not for %XML.Reader.