ITEM: T6575L

Fortran labeled common areas need to be in a specific order

Env:    AIX 3.2.5
        xlf

Desc:   Customer has a third party application which he is porting.
        The application uses fixed dimensions variables in 1 common
        block.  The Customer wants to split this up with 1 variable
        in a common block with variable dimensions.  The problem
        is that the program is written to rely on the variables
        being in contiguous memory.  When the Customer splits up
        the common block, there is no guarantee that the variables
        are stored contiguously.  The Customer wants to know if
        there is a compile option that he can use that specifies
        the order and location of common block storage.

act: 
Unfortunately there is no guarantee that the loader will load the common 
blocks contiguously, however:  
Defining the common areas together might work under the following conditions: 
 1) A reference to each common area needs to be made in the same module. 
 2) the optimizer needs to be turned off (ie. no optimizing).
A loadmap can be generated so you can see if the common blocks got loaded 
together. 



Support Line: Fortran labeled common areas need to be in a specific order ITEM: T6575L

Dated: May 1995 Category: N/A

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