RE: Based variables

["M. Lazarus" <mlazarus@xxxxxxxx>]

At 12/8/00 11:33 AM -0600, you wrote:
>The way you do this is to NOT use a field, ONLY use a pointer that is first
>Allocated to 1 record, and then Reallocated for an additional record each
>time you read another record in.  This creates a completely dynamic and
>contiguous memory block that holds the records for the file.  The externally
>described Data Structure to the file is Based on a Pointer, and you
>re-calculate this pointer to the correct position in the dynamic memory
>block.

  Let me get this straight.  If the DS is based, the pointer is set for the 
first record read.  I increment the pointer to point to the byte right 
after the DS.  How do I know I'm not stepping on some valid data in 
memory?  Do I use ALLOC / REALLOC to reserve it?  If yes, then that should 
work well.

  Does it make sense (performance wise) to only add one record to the 
memory allocation?  Or should I just add, say, 500 records worth.


>Another technique in the RPG Programmer's guide is to create a Linked List.
>The problem with this is that it requires at least 2 pointers per record,
>and possibly 3, and creates a lot of pointer management issues.  The above
>technique requires only 1 pointer for the data, and an additional pointer
>for the Based Data Structure.

  I agree that a linked list is too complicated for this application.

  -mark

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