Talk:V4 Design: epicsTypes

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Revision as of 22:06, 14 June 2005 by JeffHill (talk | contribs)

Here are my comments

1) All of the readers here probably already know that I feel that the unsigned types in C are useful. Well written code range checks operands, and unsigned operands typically require less range checking. When problems occur it's because users convert between signed and unsigned types without proper range checking. Since data access has this range checking built in (after considerable effort on mine and Ralph's part I will add) then conversion problems are possibly no longer an issue.

2) You have created interface classes for buffers, arrays, enumerated, strings etc. All of these interfaces are already in data access. Was there a good justification to create new ones? In any case, it seems that we should have the goal of using the same interfaces for each of the fundamental data types?

3) These interfaces seem to require contiguous storage of random sized blocks of characters. Doesn’t this preclude use of fixed length buffer based (free list based) memory allocation, and therefore almost guarantee fragmentation of memory. Note that fragmentation isnt just a binary condition (memory of a particular size is or isnt available). Fragmentation is also an efficency isssue because most random sized block memory allocators require searching for the best sized free block.