Marshal SizeOf

  • Thread starter Thread starter Asaf Shelly
  • Start date Start date
A

Asaf Shelly

Hi All,

I am sending a struct with a member buffer using Interop. It looks like the
marshaler knows the length of the buffer and sends only that length.
The question is how can I know the size of the buffer before it is sent?

TIA,
Asaf
 
I am sending a struct with a member buffer using Interop. It looks like the
marshaler knows the length of the buffer and sends only that length.
The question is how can I know the size of the buffer before it is sent?
Click to expand...

What is wrong with the call mentioned in the subject
line (Marshal.SizeOf) ?

Arne
 
Hi All,

I am sending a struct with a member buffer using Interop. It looks like the
marshaler knows the length of the buffer and sends only that length.
The question is how can I know the size of the buffer before it is sent?
Click to expand...

Hmmm... What are you asking? Is not the answer in your subject line?
 
Hi Arne and Tom,

The format is:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
public class TEST
{
[MarshalAs(UnmanagedType.ByValArray)]
public byte[] Buffer;
}

where buffer is allocated later. The Interop system knows to send the
correct number of bytes, so even if I specify "SizeConst = 55" and the buffer
is 15 bytes then only 15 bytes will be sent.

My problem is that I need to know in advance the number of bytes that need
to be sent because I need to notify the other end of the stream.

Any idea how the system knows the length of the object in bytes. SizeOf does
not work and I would really hate having to enumerate all members..

Thanks,
Asaf
 
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