Writing to binary file in C++ and C#

Question

Hello,

I have 2 applications. One in C++ (windows) open a binary file and only reads from it, i use:

fstream m_fsDataIN.open("C:\TTT", ios::in | ios::binary | ios::app);

and the second application (is in C#) opens the file and writes to it. I use:

byte[] b = ... //have a binary data
System.IO.BinaryWriter bw = new System.IO.BinaryWriter(
                        System.IO.File.Open(@"C:\TTT",
                        System.IO.FileMode.Append,
                        System.IO.FileAccess.Write,
                        System.IO.FileShare.ReadWrite));
bw.Write(b);
bw.Flush();
bw.Close();

The problem is that the 8 first bytes are written incorrectly, comparing to what appears in the b array.

When I open the file in the C# application, using System.IO.FileMode.Append it works OK.

I checked in the application and it writes wrong 8 bytes.

I want to add that the first 8 bytes are 2 counters that each was created using IPAddressHostToNetworkAddress.

I think that the problem is in the C++ application, in how I open the file.

Help, Thnaks

Answer 1

You've opened it just fine. But how do you read it? I think you need to call ntohl on the C++ side.

Answer 2

The problem was in the C++ application. The program contained configuration which produced another file handler. Using Process Explorer I found out about it. Removing the configuration of that extra file handler resolved the problem.