Marshaling is engaged in any case. In some cases, however, as J.Merrill pointed out, the marshaling is trivial and does not involve actual data transformations.
Managed-unmanaged code interactions, be it IJW or "true" P/Invoke always require marshaling. You can get perf gains from IJW just because you don't need to load additional DLLs, but that's about it. No perf difference due to marshaling. Thanks, Serge -----Original Message----- From: Discussion of advanced .NET topics. [mailto:[EMAIL PROTECTED] On Behalf Of J. Merrill Sent: Tuesday, November 29, 2005 12:50 PM To: [email protected] Subject: Re: [ADVANCED-DOTNET] Difference between PInvoke and IJW I'd say that it's pretty hard to comment definitively without info about what unmanaged code is being called, and what C++ data is being passed. Do you have any samples? You seem pretty confident that PInvoke is always slower, when I don't see how that can be true in every case (or how you could have tested every case). The marshaling from managed to unmanaged types can only be skipped if the data being passed is already in a format usable by the unmanaged code. For example, C-style (null-terminated) strings (not managed strings declared with __gc) are in the form that most API calls expect, so no marshaling is needed there. But in most other cases, some kind of marshaling is needed. At 06:26 PM 11/28/2005, Muhammad Adel wrote >Hello >I would like to know what is the cause in performance difference between the >PInvoke and the IJW methods. Is the marshaling of data from managed to >unmanaged types skipped when using the IJW method? >Thanks in advance. > >Muhammad Adel > <http://mohammadadel.blogspot.com/> My blogs J. Merrill / Analytical Software Corp =================================== This list is hosted by DevelopMentor(r) http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com =================================== This list is hosted by DevelopMentor® http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com
