Technical data

26
Chapter 2: Storage Mapping
• You must explicitly declare an array in a DIMENSION declaration or
in a data type declaration. To support dimension, the compiler
– allows up to seven dimensions
– assigns a default of 1 to the lower bound if a lower bound is not
explicitly declared in the DIMENSION statement
– creates an array the size of its element type times the number of
elements
– stores arrays in column-major mode
• The following rules apply to shared blocks of data set up by the
COMMON statements:
– The compiler assigns data items in the same sequence as they
appear in the common statements defining the block. Data items
will be padded according to the alignment switches or the default
compiler. See “Access of Misaligned Data” on page 27 for more
information.
– You can allocate both character and noncharacter data in the same
common block.
– When a common block appears in multiple program units, the
compiler allocates the same size for that block in each unit, even
though the size required may differ (due to varying element names,
types, and ordering sequences) from unit to unit. The size allocated
corresponds to the maximum size required by the block among all
the program units except when a common block is defined by using
DATA statements, which initialize one or more of the common
block variables. In this case the common block is allocated the same
size as when it is defined.