Blurb::
Name the interface block; helpful when there are multiple

Description::
The optional \c id_interface keyword accepts a string that uniquely
identifies this interface block.  A model can then use this interface
by specifying the same string in its \c interface_pointer
specification.

<b>Default Behavior</b>

If the \c id_interface specification is omitted, a particular
interface specification will be used by a model only if that model
does not include an \c interface_pointer and the interface block was
the last (or only) one parsed.

<b>Usage Tips</b>
- It is a best practice to always use explicit interface IDs and
  pointers to avoid confusion.

- If only one interface block exists, then \c id_interface can be
  safely omitted from the interface block (and \c interface_pointer
  omitted from the model specification(s)), since there is no
  ambiguity.


Topics::	block_identifier

Examples::
For example, a model specification including
\verbatim
model
  interface_pointer = 'I1'
\endverbatim
will link to an interface with 
\verbatim
id_interface = 'I1'
\endverbatim

Theory::
Faq::
See_Also::	
