//----------------------------------------------------------------------------
// Copyright (C) 2013-2015 Fabrice HARROUET (ENIB)
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation.
// The author makes no representations about the suitability of this
// software for any purpose.
// It is provided "as is" without express or implied warranty.
//----------------------------------------------------------------------------

using System;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;

public class Test
{
/***
  "msvcrt" is used in DllImport
  This is the standard C library for Windows
  .NET loads "msvcrt.dll"
  Mono maps it to "libc.so.6" or "libc.dylib" (through /etc/mono/config)
***/
const string stdLibName="msvcrt";

[DllImport(stdLibName)]
public static extern
int
getpid();

[DllImport(stdLibName)]
private static extern
IntPtr
strncpy(StringBuilder dest,
        string src,
        int n);

[DllImport(stdLibName)]
private static extern
IntPtr
strerror(int errnum);

public struct MyStruct
  { 
  [MarshalAs(UnmanagedType.U1)]
  public bool b;
  public byte c;
  public short s;
  public int i;
  public long l;
  public float f;
  public double d;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst=16)]
  public string t; 
  }

/***
  "myNativeLib" is used in DllImport
  .NET loads "myNativeLib.dll" (near to the assembly)
  Mono loads "libmyNativeLib.so" or "libmyNativeLib.dylib"
***/
[DllImport("myNativeLib",EntryPoint="myNativeFunction")]
private static extern
void
myFunction(ref MyStruct ms);

public static
void
Main(string[] args)
  {
  Console.WriteLine("testing getpid()");
  try
    {
    int pid=getpid();
    Console.WriteLine("--> {0}",pid);
    }
  catch(Exception e)
    {
    Console.WriteLine("!!! Exception: {0}",e);
    }
  Console.WriteLine("testing strncpy()");
  try
    {
    StringBuilder sb=new StringBuilder(256);
    strncpy(sb,"copy this message",sb.Capacity);
    Console.WriteLine("--> {0}",sb.ToString());
    }
  catch(Exception e)
    {
    Console.WriteLine("!!! Exception: {0}",e);
    }
  Console.WriteLine("testing strerror()");
  try
    {
    IntPtr p=strerror(4); // 4: EINTR
    string s=Marshal.PtrToStringAnsi(p);
    Console.WriteLine("--> {0}",s);
    }
  catch(Exception e)
    {
    Console.WriteLine("!!! Exception: {0}",e);
    }
  Console.WriteLine("testing myFunction()");
  MyStruct ms;
  ms.b=false;
  ms.c=1;
  ms.s=2;
  ms.i=3;
  ms.l=4;
  ms.f=5.5f;
  ms.d=6.6;
  ms.t="input";
  try
    {
    myFunction(ref ms);
    Console.WriteLine("--> {0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}",
                      ms.b,ms.c,ms.s,ms.i,ms.l,ms.f,ms.d,ms.t);
    }
  catch(Exception e)
    {
    Console.WriteLine("!!! Exception: {0}",e);
    }
  }
}

//----------------------------------------------------------------------------