The "try to read or write protected memory" issue when C # calls Haskell

Has been plagued by the "attempt to read or write protected memory" issue when C # was called Haskell (see the C # call Haskell encounter attempted to read or write protected memory,c# when invoking Haskell). Attempt to read or write protected memory "problem", and trapped in it, the more deep, unable to extricate themselves, almost abandoned with C # to solve the problems we face.

The problem is that, as long as the string is manipulated in the Haskell code, an exception is thrown when the C # call is made:

An unhandled exception of type ' system.accessviolationexception ' occurred in Unknown Module.

Additional information:attempted to read or write protected memory. This is often a indication that the other memory is corrupt.

The example Haskell code is as follows:

If you return a string directly, everything works, and the example Haskell code is as follows:

C # invokes sample code:

Class Native
{
    [DllImport ("Libpandoc", CallingConvention = callingconvention.cdecl, CharSet = CharSet.Unicode )] public
    static extern IntPtr markdowntohtml (byte[] markdown);
   
public class Processor 
{public
    string Process (string text)
    {
        var intPtr = native.markdowntohtml ( System.Text.Encoding.UTF8.GetBytes (Text));
        var html =  Marshal.ptrtostringansi (intPtr);
        return html;
    }