PInvoke question

[shankgreen]

My question is related to what happens under the hood when marshalling
happens.
When you pass a pointer to a structure from managed to unmanaged, and
if the unmanaged code modified the structure, is the structure copied
from the stack to unmanaged heap and then back or is it modified in
the stack itself.

If it is modifed within the stack itself, what about a managed
structure which has an array reference inside?

[Mattias Sjögren]

>When you pass a pointer to a structure from managed to unmanaged, and
if the unmanaged code modified the structure, is the structure copied
from the stack to unmanaged heap and then back or is it modified in
the stack itself.

It depends on whether or not the type is "blittable" (ie if it only
contains types that have the same representation on the managed and
native side or not). This page in the docs provide a pretty good
overview

http://msdn2.microsoft.com/en-us/lib...7k(VS.80).aspx
Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[amaldevc]

On Feb 16, 11:26 pm, Mattias Sjögren <[e-mail]>
wrote:

When you pass a pointer to a structure from managed to unmanaged, and
if the unmanaged code modified the structure, is the structure copied
from the stack to unmanaged heap and then back or is it modified in
the stack itself.

It depends on whether or not the type is "blittable" (ie if it only
contains types that have the same representation on the managed and
native side or not). This page in the docs provide a pretty good
overview

http://msdn2.microsoft.com/en-us/lib...7k(VS.80).aspx

Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.orghttp://www.msjogren.net/dotnet/|http://www.dotnetinterop.com
Please reply only to the newsgroup.

Thank u man