Re: Sockets on Windows (and DuplicateHandle, CloseHandle)

[Fan Chun-wei <fanc999 yahoo com tw>]

(Sorry, resending as e-mail was accidently not sent to the list)

Hello Ryan,

Few of my quick thoughts...
> ...
> What I want to know:
>
>   - are LSPs the only reason that I can't use CloseHandle and
>   DuplicateHandle on
>     socket handles (ie: if there are no LSPs around, will everything be
>     OK)?
I don't think so.  Saw this thread with this quick search: 
http://microsoft.public.win32.programmer.networks.narkive.com/EoNck2gO/does-closesocket-call-closehandle-internally. 


The MSDN documentation explicitly states that one should not use 
CloseHandle/DuplicateHandle on sockets, due to internal resource 
management issues.

https://msdn.microsoft.com/en-us/library/windows/desktop/ms724211%28v=vs.85%29.aspx 

https://msdn.microsoft.com/en-us/library/windows/desktop/ms724251%28v=vs.85%29.aspx 

>   - how common are LSPs in practice?
They could be used in parental control programs (it is done as a LSP 
Vista's and 7's parental controls) and anti-virus/anti-malware programs 
as well, such as in older Avira and Sophos, so could be widespread.

https://msdn.microsoft.com/en-us/library/windows/desktop/ms711710%28v=vs.85%29.aspx 


For the last 2 questions, need to look further, but this is what I can 
find out at this point.

With blessings.