4.2 BLOCK DATA Statement

A BLOCK DATA statement initiates a series of specification statements that establish common blocks and assign initial values to the entities in named common blocks.

The BLOCK DATA statement takes the following form:

BLOCK DATA [nam]

nam

Is a symbolic name.

Rules and Behavior

A BLOCK DATA statement and its associated specification statements are a special kind of program unit, called a block data subprogram.

Any of the following specification statements can appear in a block data subprogram:

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 specification 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.

Example

The following example shows a valid block data subprogram:

BLOCK DATA BLKDAT
INTEGER S,X
LOGICAL T,W
DOUBLE PRECISION U
DIMENSION R(3)
COMMON /AREA1/R,S,T,U /AREA2/W,X,Y
DATA R/1.0,2*2.0/, T/.FALSE./, U/0.214537D-7/, W/.TRUE./, Y/3.5/
END

For More Information:

• On the DATA statement, see Section 4.4.

• On the EXTERNAL statement, see Section 4.8.

• On the END statement, see Section 5.5.