Visible to Intel only — GUID: GUID-1E8543B7-B358-4F7F-8C70-15CDD5A333F4
Visible to Intel only — GUID: GUID-1E8543B7-B358-4F7F-8C70-15CDD5A333F4
EQUIVALENCE and COMMON Interaction
A common block can extend beyond its original boundaries if variables or arrays are associated with entities stored in the common block. However, a common block can only extend beyond its last element; the extended portion cannot precede the first element in the block.
Examples
The following two figures demonstrate valid and invalid extensions of the common block, respectively.
![](/content/dam/docs/us/en/developer-guide-reference/2024-2/16716735-DF07-4A78-BC22-25A560AF1FB9-low.jpg)
![](/content/dam/docs/us/en/developer-guide-reference/2024-2/DF6D660C-C38C-4ECA-B239-AED568FD881B-low.gif)
The second example is invalid because the extended portion, B(1), precedes the first element of the common block.
The following example shows a valid EQUIVALENCE statement and an invalid EQUIVALENCE statement in the context of a common block.
COMMON A, B, C
DIMENSION D(3)
EQUIVALENCE(B, D(1)) ! Valid, because common block is extended
! from the end.
COMMON A, B, C
DIMENSION D(3)
EQUIVALENCE(B, D(3)) ! Invalid, because D(1) would extend common
! block to precede A's location.