convert struct en byte

There is no standard method of doing this, as it depends on what types you have in your struct, and what restrictions you have.

For instance, if you're not concerned with optimal speed and space, you could stream the struct to/from XML (this is relatively trivial in C#, but more complicated in C++) and send the XML string as a byte array.

Keep in mind that even simple types are not necessarily the same size in C# and C++, and floating point numbers in particular will have different memory layout. That's why they are often transferred as text, or broken up into exponent and mantissa.

>> how I can convert a structure to a byte tbleau array

struct A
{ int i; };


A a;

char* ptr_to_array = (char*)&a;

You don't need to convert the structure, it is after all just an array of bytes already ...

As for roundtripping through .Net (c#) - you should perhaps use System.IntPtr[^], or perhaps something else - as it's not entirely clear what you want.

Best regards
Espen Harlinn

In C#, int is a signed 32-bit value, which gives a 4-byte array, so you could just write those bytes to the array like this:

void IntToArray(int val, byte[] array, int index)
{
    // Convert int to uint to make bit handling tidier
    uint temp = unchecked((uint)val);
    for (int i = 0; i < 4; ++i)
    {
        array[index + i] = (byte)((temp >> i*8) & 0xff);
    }
}

byte[] StructAToArray(A a)
{
    byte[] array = new byte[8 + a.T.Length];
    // First int
    IntToArray(a.a, array, 0);
    // Second int, 4 bytes later
    IntToArray(a.b, array, 4);
    // Array, 4 bytes later again
    Array.Copy(a.T, 0, array, 8, a.T.Length);
    // Done
    return array;
}

Then you just have to do the corresponding conversion on the C++ side. :-)