Re: A confusion about the stream interface driver

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Steve Maillet \(eMVP\) (nospam1_at_EntelechyConsulting.com)
Date: 03/25/05 

Date: Fri, 25 Mar 2005 10:44:25 -0500

The exact same thread of the application is what runs in the driver the
system simply changes the process context the thread is running in. (look up
"Thread Migration" in the help or google for more details) All of the
pointers that the application passes as direct parameters to system APIs are
automatically adjusted so that the system process can access them. However,
any pointers embedded in the data those direct pointers refer to are NOT
automatically adjusted and the driver MUST use MapCallerPtr() to map them
for access from the driver. (This is because the OS cannot possibly know if
the pointer you passed points to an array of pointers or a blob of data -
only the driver would know) 

-- 
Steve Maillet
EmbeddedFusion
www.EmbeddedFusion.com
smaillet at EmbeddedFusion dot com

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