According to this, optional arguments are 'filled in' to their default values, by the compilers of languages that support them. It also says that the default values should be clearly documented.

The upshot appears to be that you will have to pass the default values when calling from a language that does not support this behaviour. So, you will need to look up the dfault values and provide them explicitly either every time you call via Win32::API or supply a wrapper function that fills them in.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

In reply to Re^3: functions with optional arguments in Windows DLLs by BrowserUk
in thread functions with optional arguments in Windows DLLs by spurperl

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