Section 13,10: BLOCK_DATA

 Begins a block data program unit.  Statement format:

    BLOCK DATA [nam]

    nam   Is the symbolic name used to identify the block.  

 A BLOCK DATA statement and its associated specification statements
 are a special kind of program unit, called a block data subprogram.
 The block data subprogram has the following syntax rules:

    - Any of the following specification statements can appear 
      in a block data subprogram:
      
      COMMON             RECORD
      DATA               SAVE
      DIMENSION          STATIC
      EQUIVALENCE        Structure declaration
      IMPLICIT           Type declaration statements
      PARAMETER

    - A block data subprogram must not contain any 
      executable statements.

    - As with other types of program units, the last 
      statement in a block data subprogram must be an 
      END statement.

    - Within a block data subprogram, if a DATA statement 
      initializes any entity in a named common block, 
      the subprogram must have a complete set of speci-
      fication statements that establishes the common block.  
      However, all of the entities in the block do not have 
      to be assigned initial values in a DATA statement.

    - One block data subprogram can establish and define 
      initial values for more than one common block.

    - The name of a block data subprogram can appear in the 
      EXTERNAL statement of a different program unit to force 
      a search of object libraries for the BLOCK DATA program 
      unit at link time.