On 3/18/2011 9:38 AM, Dennis wrote:
Ah, that sheds some light! Since we have no (apparent) means of
telling QZRUCLSP that certain parameters are optional but passed, it
seems unlikely that it would be capable of guessing the correct means
of passing same.

Probably a moot point, but is the "differently" part of your message
a trade/business/compiler secret?

It's more that I don't know all the details since it's mostly transparent to the compilers. The compilers just tell the optimizating translator that the called function has optional parameters.

I do know that for a "..." C function, the function would use the va_list mechanism to access optional parameters. This requires that the optional parameters be contiguous in storage, so parameter 3 follows parameter 2 in storage, at a fixed offset away. When there are no optional parameters, the system can pass the parameters in whatever way makes the most sense. So the location of parameter 3 can't be predicted from the location of parameter 2.

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