Walter wrote:
<snip>
>>I disagree.  The end user isn't going to be calling OS API functions
>>directly, any more than functions in the library being talked about or
>>functions in the app itself.
> 
> Yes, they do. I call OS API functions all the time in my code.

You mean when you're doing word processing, graphic design, browsing the web, playing games or whatever, you type in random API calls to be executed?

<snip>
> Any OS API or DLL interface must consider all programs trying to connect to
> its functions as rogue, and must do parameter validation on them.

Yes.  But a lib might also do its own checks as an added safety net. These might be done by either DbC or by checks in the release code. E.g. to make the lib functions fail-fast, or to translate vague zero return values into context-sensitive exceptions.

Stewart.

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