Marshalling dynamic size array into struct

Question

how can i define a struct with a dynamic sized array?

is it right?

struct MyStruc { 

    public int len; 
    [MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)]
    public int buf[]; 
}

Answer 1

Assuming that you want a struct containing a pointer to the array.

Declare the pointer to the array as IntPtr and marshal the array contents manually with Marshal.AllocHGlobal, Marshal.Copy etc.

Assuming that you want a variable sized struct rather than a struct containing a pointer to the array.

You cannot marshal a variable sized struct using p/invoke. You have at least these two options:

1. Break the struct into two parameters.
2. Marshal the struct manually with Marshal.AllocHGlobal, Marshal.Copy etc.