Re: [DotGNU]Calling C

[Rhys Weatherley]

On Wednesday 30 April 2003 03:44 am, Chris Smith wrote:

> So what is the most appropriate mechanism for doing this with pnet
> PInvoke or that internalCall technique Gopal was talking about?
> I'm concerned with cross-platform-ness here (assuming gpgme is cross
> platform too).

Assuming that pgpme is cross-platform and its C API is relatively clean, 
PInvoke should work reasonably portably, even on Windows.  There may be some 
32-bit vs 64-bit issues (e.g. if gpgme uses "long" then that is different 
sizes on 32-bit vs 64-bit platforms).  If you isolate the PInvoke stuff in 
one class, then modifying the marshalling rules for system-specifics should 
be pretty easy.

> So what's concensus? Pinvoke my libs or internalCall - internalCall is more
> efficient isn't it?

Not really.  Internalcall doesn't perform any marshalling in the call 
mechanism.  e.g. unpack an object and convert it into the paramters expected 
by the C API.  PInvoke does it automatically, but internalcalls require you 
to do it by hand.  It works out about even performance-wise.

Internalcall was designed for manipulating engine objects, which don't need to 
be converted into a different form first to be useful.

Cheers,

Rhys.