Use windows C++ API in dotnet

  • Thread starter Thread starter Usman
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Usman

Hi

Can someone please tell me how to use C++ API in c# code. Like I have to use
the functionality of memcpy in my C# code. I have to copy the bytes of an
integer variable to 4 character bytes to convert it to string, if there's
any alternative to this in C#, please recommend otherwise tell me how can I
use memcpy itself in C# code.

Regards

Usman Jamil
 
Usman said:
Hi

Can someone please tell me how to use C++ API in c# code. Like I have to use
the functionality of memcpy in my C# code. I have to copy the bytes of an
integer variable to 4 character bytes to convert it to string, if there's
any alternative to this in C#, please recommend otherwise tell me how can I
use memcpy itself in C# code.
Click to expand...

First of all, there is no C++ Windows API (with the marginal exception
of GDI+) : All the Windows native API is C, not C++.

Next, memcpy is a CRT API, it is not part of the Windows API (whereas
RTLCopyMemory is).

To finish with, in your particular case, your best bet is to use the
BitConverter.GetBytes method.

Arnaud
MVP - VC
 
Usman said:
Hi

Can someone please tell me how to use C++ API in c# code. Like I have to
use
the functionality of memcpy in my C# code. I have to copy the bytes of an
integer variable to 4 character bytes to convert it to string, if there's
any alternative to this in C#, please recommend otherwise tell me how can
I
use memcpy itself in C# code.
Click to expand...

For Win32 API, like CopyMemory, see http://pinvoke.net
The pure .NET version is System.Runtime.InteropServices.Marshal.Copy (still
requires unmanaged code permission).

However, for your need, I don't think CopyMemory is going to help you (it's
the exact windows analogue to the ANSI C runtime function memcpy).

If you are ok with using the machine byte ordering, you can just use an
unsafe code block and cast a pointer (simplest, fastest).
For verifiability,
create a MemoryStream
use a BinaryWriter to write your data
use the MemoryStream's ToArray() method to get the raw bytes.

In reverse, you can construct a memory stream from an array of bytes, then
use BinaryReader to get back typed variabled.

However, this seems very expensive.

Does anyone know of any method for doing this in verifiable code (not
expecting to see the insides of references, only value types) without
creating a bunch of extra objects? I know you could reuse the same
BinaryWriter/MemoryStream by calling Seek(), but it will still allocate a
new byte[] for each call to ToArray, right?
 
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