C# and 'memory buffers'

[Mike Smith]

I've been working with C++ for years and am strugling at C#. I am trying to
reuse a COM object that I wrote that takes a chacter buffer and a size of
the buffer. I am having a problem "filling" in the memory buffer to pass to
my COM object. An example might be more explanatory.

public struct Data
{
ushort data_id;
ushort data_size;
}

Data my_data;
sbyte buf = new sbyte[8];

How do I copy the data structure into the buf array. Note that my data
structure can be any structure and can be variable length, thats why I can't
just to a simple ushort array. In C++ I would do something like this,
memcpy( buf, my_data, my_data.data_si ze ). I really can't seem to get my
mind around how to do this in C#.

Any help would be greatly appreciated.

Mike

[Chris Dunaway]

Re: C# and 'memory buffers'

Mike Smith wrote:

I've been working with C++ for years and am strugling at C#. I am trying to
reuse a COM object that I wrote that takes a chacter buffer and a size of
the buffer. I am having a problem "filling" in the memory buffer to pass to
my COM object. An example might be more explanatory.
>
public struct Data
{
ushort data_id;
ushort data_size;
}
>
Data my_data;
sbyte buf = new sbyte[8];
>
How do I copy the data structure into the buf array. Note that my data
structure can be any structure and can be variable length, thats why I can't
just to a simple ushort array. In C++ I would do something like this,
memcpy( buf, my_data, my_data.data_si ze ). I really can't seem to get my
mind around how to do this in C#.

Have a look at Marshal.Copy in the System.Runtime. InteropServices
namespace.

[Chris Dunaway]

Re: C# and 'memory buffers'

Mike Smith wrote:

How do I copy the data structure into the buf array. Note that my data
structure can be any structure and can be variable length, thats why I can't
just to a simple ushort array. In C++ I would do something like this,
memcpy( buf, my_data, my_data.data_si ze ). I really can't seem to get my
mind around how to do this in C#.

Actually Marshal.Structu reToPtr and Marshal.PtrToSt ructure would
probably be more helpful.

[Mike Smith]

Re: C# and 'memory buffers'

Since there were no replies I can only assume that C++ is a more "superior"
language than C#? Just poking fun. Does any have an idea where I can
start?

"Mike Smith" <MikeSmith@some where.comwrote in message
news:OrS9Nu2AHH A.4256@TK2MSFTN GP04.phx.gbl...

I've been working with C++ for years and am strugling at C#. I am trying
to reuse a COM object that I wrote that takes a chacter buffer and a size
of the buffer. I am having a problem "filling" in the memory buffer to
pass to my COM object. An example might be more explanatory.
>
public struct Data
{
ushort data_id;
ushort data_size;
}
>
Data my_data;
sbyte buf = new sbyte[8];
>
How do I copy the data structure into the buf array. Note that my data
structure can be any structure and can be variable length, thats why I
can't just to a simple ushort array. In C++ I would do something like
this, memcpy( buf, my_data, my_data.data_si ze ). I really can't seem to
get my mind around how to do this in C#.
>
Any help would be greatly appreciated.
>
Mike
>

[Willy Denoyette [MVP]]

Re: C# and 'memory buffers'

Can you show us your COM interface definition, IDL or tlb is what we are
looking for. The reason is that you probably don't need to copy anything,
this is something that is taken care of by the COM interop layer in the CLR,
unless you pass arguments that cannot be handled by the COM layer, in which
case you'll need to implement custom marshalin.

Willy.


"Mike Smith" <MikeSmith@some where.comwrote in message
news:%23HzpOPMC HHA.4348@TK2MSF TNGP04.phx.gbl. ..
| Since there were no replies I can only assume that C++ is a more
"superior"
| language than C#? Just poking fun. Does any have an idea where I can
| start?
|
| "Mike Smith" <MikeSmith@some where.comwrote in message
| news:OrS9Nu2AHH A.4256@TK2MSFTN GP04.phx.gbl...
| I've been working with C++ for years and am strugling at C#. I am
trying
| to reuse a COM object that I wrote that takes a chacter buffer and a
size
| of the buffer. I am having a problem "filling" in the memory buffer to
| pass to my COM object. An example might be more explanatory.
| >
| public struct Data
| {
| ushort data_id;
| ushort data_size;
| }
| >
| Data my_data;
| sbyte buf = new sbyte[8];
| >
| How do I copy the data structure into the buf array. Note that my data
| structure can be any structure and can be variable length, thats why I
| can't just to a simple ushort array. In C++ I would do something like
| this, memcpy( buf, my_data, my_data.data_si ze ). I really can't seem to
| get my mind around how to do this in C#.
| >
| Any help would be greatly appreciated.
| >
| Mike
| >
|
|

[Chris Dunaway]

Re: C# and 'memory buffers'

Mike Smith wrote:

Since there were no replies I can only assume that C++ is a more "superior"

No replies? I pointed out this:

"Actually Marshal.Structu reToPtr and Marshal.PtrToSt ructure would
probably be more helpful. "