Calling C Library DLLs from C Sharp

[KYAW KYAW OO]

Dear All,

I am trying to call the data type unsigned char * included in the C DLL and whole structure from C Sharp.
My draft code is below

[StructLayout(LayoutKind.Sequential, Pack = 1, CharSet = CharSet.Unicode)]
        public struct Converted
        {
            public int width;
            public int height;
            public IntPtr Buf;  // which is unsigned char* in C and is it           correct ?
            //[MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
 
        };
 
Converted c = new Converted();
[DllImport("Test.dll", CharSet = CharSet.Auto, EntryPoint="Loading")]
public static extern Converted Loading(ref IntPtr buf, int size, int type); // shoul I use ref?
 
i.data is syste.array
c.Buf = Loading(ref i.data, i.size, type);
 
 

I encountered
1. to pass unsigned char * from C to C#
2. return structure of Converted from C to C#
3. System.array of C# to IntPtr of C# or unsigned char *

I hope some one will advise me to get it well for my dll and looking forward to hearign from you soon.


Thanks in advance

[KYAW KYAW OO]

Dear All,

I am trying to call the data type unsigned char * included in the C DLL and whole structure from C Sharp.

My draft code is below

// dll.cpp
// Image Display and BufferMemory
typedef
struct ConvertedImage 
{
int height; 
int size; 
unsigned char *greyBMPBuf; 
}ConvertedImage; 
 
MATCH_IMPORTS ConvertedImage Convert2BMPGrey(unsigned char *bufFromDevice, int size, int image_type);
 
// main.cs
[StructLayout(LayoutKind.Sequential, Pack = 1, CharSet = CharSet.Unicode)] 
public struct ConvertedImage 
{
public int width; 
public int height; 
public int size; // size = imagesize is imagewidth * imgaeheight 
[MarshalAs(UnmanagedType.LPArray)] 
public byte[] greyBMPBuf; 
};
 
ConvertedImage cImage; 
 
[DllImport("Match.dll", CharSet = CharSet.Auto, EntryPoint = "Convert2BMPGrey")] 
public static extern ConvertedImage Convert2BMPGrey([MarshalAs(UnmanagedType.LPArray)]byte[] bufImage, int size, int image_type); 
 

I encountered
1. to pass unsigned char * from C to C#
2. return structure of Converted from C to C#
3. System.array of C# to IntPtr of C# or unsigned char *
4. the error message"Method's type signature is not PInvoke compatible"

Please advise me for my dll and C# InteropServices and looking forward to hearing from you good news.


Thanks in advance

[tlhintoq]

Please don't double-post your questions. It divides attempts to help you in an organized and cohesive manner. Your threads have been merged