how do I declare fixed-size array of a structure type in C# :
[StructLayout(LayoutKind.Sequential,Pack=1), Serializable]
public unsafe struct MyStruct{
...
}
public class MyClass {
...
public fixed MyStruct myStruct[256];
}
this will result to CS1663 : fixed size buffers of struct type is not allowed, how do I workaround this ?, I prefer not to use C# or "Managed Collection data structure" type, as I need to frequently marshall this to native C++
If your C# struct uses only primitive data types and has exactly the same layout as your native struct in C++, you can get around these restrictions with manual memory management and unsafe code. As a bonus, you will improve performance by avoiding marshalling.
Allocate the memory:
IntPtr arr = Marshal.AllocHGlobal (sizeof (MyStruct) * 256);
This is basically malloc, so the allocated memory is outside the awareness of the GC.
You can pass the IntPtr to native code as if it were a MyStruct[256] and only the IntPtr will be marshalled, not the memory it points to. Native and managed code can access the same memory directly.
To read/write the structs in the array with C#, use C# pointers:
static unsafe MyStruct GetMyStructAtIndex (IntPtr arr, int index)
{
MyStruct *ptr = ((MyStruct *)arr) + index;
return *ptr;
}
static unsafe void SetMyStructAtIndex (IntPtr arr, int index, MyStruct value)
{
MyStruct *ptr = ((MyStruct *)arr) + index;
*ptr = value;
}
Don't forget to
Marshal.FreeHGlobal (arr);
when you're done with the memory, to free it.
You can't; per the definition
The only restriction is that the array type must be
bool,byte,char,short,int,long,sbyte,ushort,uint,ulong,float, ordouble.
