exodus_updates.txt

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*** Permit 0 as valid entity (block, set, map) id

* Version 5.09 -- Modifications to let zero be a valid entity (element
	block, nodeset, sideset, map, other sets and blocks).  There is a
	new define EX_INVALID_ID (-1) which now indicates that the id for
	an entity has not yet been set.  All positive integers are now
	valid id values.

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*** Long Name support.

   Exodus from version 5.08 and later can support names of length up
   to NC_MAXNAME which is currently 256.  The internals of the exodus
database have changed with the addition of a new 'dimension' and a new
database attribute.

This has the following implications:
*. The old library can read a new database if the new database does
   not use names longer than 32 characters.

*. If the new database uses longer names, the old library will crash.

*. New library with old database will work fine.

*. New library with new database, no code changes.  If the database
   uses long names, they will be truncated (with message to stderr) at
   32 characters.  An output database will limit names to 32
   characters by default.

The following code changes are used to work with long names:

========================================
Reading a database:

* Query a database for the maximum length of a name stored on the
  database.  This does not include the space for the trailing null.

     int max_name_length = ex_inquire_int(exoid,
		    EX_INQ_DB_MAX_USED_NAME_LENGTH);

* Tell the exodus API the maximum name length that your client code
  can handle.  This is the size of the character strings that are
  passed to the ex_get_names() and similar calls.  Note that the
  maximum_length does not include the trailing null.  That means that
  if you tell the library to give you 32-character names, the memory
  buffer you pass to the library must be 33 characters.

    int status = ex_set_max_name_length(exoid, maximum_length);

  If this size is less than the length of a name on the database, the
  name will be truncated and a message printed to stderr.

* Inquire the size set for the max_name_length. Will return 32 by
  default, or if ex_set_max_name_length was called, it will return the
  size set in that call.

     int max_name_length = ex_inquire_int(exoid,
		    EX_INQ_CUR_MAX_ALLOWED_NAME_LENGTH);
    
* Inquire the size that the database used at creation time for the
  maximum name size.  This is the value used for
  ex_set_max_name_length() when the database was created. This isn't
  really needed unless you are appending to an existing database and
  want to know how long of names it will support.

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Writing a database:

* After the ex_create() call and before the call to ex_put_init() or
  ex_put_init_ext(), call ex_set_max_name_length(exoid, max_length); to
  tell the database the maximum size names that you will be
  outputting. If this isn't called, then it will default to 32
  character names.

* The code will keep track of the maximum length that was written and
  will update an attribute on the database with that length.  This is
  queryable via the following function:

     int max_name_length = ex_inquire_int(exoid,
		    EX_INQ_DB_MAX_USED_NAME_LENGTH);


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Names that are included:

* Entity names (element block, nodeset, sideset, faceblock, ...)
* Attribute names
* Map names
* Results variable names

Still 32 characters:
* QA strings
* element type in ex_get_block, ex_put_block calls.

Still 80 characters:
* info records
* title.

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Questions / Concerns / Problems:

Greg Sjaardema.
gdsjaar@sandia.gov or gsjaardema@gmail.com