This thread is for discussions of Binary Files.

Since you can do the same kind of stuff like this and save it to the registry, which is easier, why use binary files?  I could see it if you had a LOT of values, but then wouldn't you just use and INI file or something for conveienience?  I guess keeping things secret, like passwords, you might use a bin file for, but what could it be used for other than that?

This is a 2 ways method, if your program very much independent on settings inside the INI files you just have to read and write the INI files at all times.

Or if ur program is mostly put the value inside the registry for a one-time settings of something in conjunction to the system setting, registry would be better.

But i prefer using INI files since it can be separated from the syste, registry and avoid corruption.

One more thing is in registry, you can organize ur setting in parent and child relationship but not INI file.

The Len() function returns null if the file is open in binary mode. Use the LOF() function instead.

Another thing, String() function is better to use than Space() function because if you have used value bigger than new value, Space() only fills string with spaces, leaving the size as is, but String() resizes the strng.

And don't forget, data files shouldn't be written to the registry.

Is it possible to read a C++ written binary file into visual basic and write it again using vb then have it read by c++. If it is then can someone please tell me. also how do you write a typefef structure into a file using c++. Does anyone know. I would really appreciate it.

Quote:

[1]Posted by TheShotGunnner on 24 Nov 2002 09:16 PM[/1]
Is it possible to read a C++ written binary file into visual basic and write it again using vb then have it read by c++. If it is then can someone please tell me. also how do you write a typefef structure into a file using c++. Does anyone know. I would really appreciate it.

A binary file is a binary file regardless of which language creates it.  The following code reads in a binary file 2 bytes at a time (the read statement) and then writes them to another binary file 2 bytes at a time (the write statement)
#include <fstream.h>
#include <iomanip.h>
int main()
{
   int ind, tot;
   unsigned char byte[2];
   ifstream infile("2000_09_28_18_40_11_Sen2_Grp0.dat", ios::in );
   ofstream outfile("test.dat", ios::binary );

   for ( ind = 1; ind <= 20; ind++ )
   {
       infile.read( byte, 2 );
       outfile.write( byte, 2 );
       tot = byte[0] + ( byte[1] << 8 );
       cout << setw(8) << ind << setw(8) << tot << setw(8) << (int)byte[0] << setw(8) << (int)byte[1] << endl;
   }
   return 0;
}

I plan to test test.dat later and make sure that VB can read it.  But I have little doubt that it will.  You may wonder what I was writing to the screen with cout.  (This is important to consider.)    Often binary files contain 2 byte integers split into two separate bytes.  Here I was taking the bytes and recombining them into their original value. For example the first two number that are read are 208(byte[0] ) and 7 (byte[1]).  Shifting the the 1 byte 7 8 places (the equivalent of multiplying by 256) and then adding it to byte[0] to make an integer 2 bytes long equals 2000.  7 * 256 + 208 = 1792 + 208 = 2000 or looked at another way 00000111 010110000 is a 16 bit representation of 2000.

I hope this helps.

David

thanx

Hi Shotgunner,
I assumed that a binary file that could be read by C/C++ could also be read in VB.  There are constraints on how to do that but here goes.  In the code I posted before I created a binary file.  Here's the code I used to read it and write out the equivalent integer (or more correctly long) data in VB:
Private Sub cmdRead_Click()
   Dim ibyte(2) As String * 1
   Dim tot, temp As Long
   Dim ind As Integer
   For ind = 0 To 19
       Get #1, , ibyte(1)
       Get #1, , ibyte(2)
       temp = Asc(ibyte(2)) * 2 ^ 8
       tot = Asc(ibyte(1)) + temp
       txtData(ind * 3).Text = tot
       txtData((ind * 3) + 1).Text = Asc(ibyte(1))
       txtData((ind * 3) + 2).Text = Asc(ibyte(2))
   Next ind
End Sub

Private Sub mnuExitProgram_Click()
   Unload frmBin
End Sub

Private Sub mnuFileOpen_Click()
   Open "test.dat" For Binary As #1
   cmdRead.Enabled = True
End Sub

Obviously I won't be sending you the forms.
Here's the C (or more correctly the VC++ ) code that accomplishes a similar purpose:

#include <fstream.h>
#include <iomanip.h>
int main()
{
   unsigned ind, tot;
   unsigned char byte[2];
   ifstream infile("test.dat", ios::in );

   for ( ind = 1; ind <= 20; ind++ )
   {
       infile.read( byte, 2 );
       tot = byte[0] + ( byte[1] << 8 );
       cout << setw(8) << ind << setw(8) << tot << setw(8) << (int)byte[0] << setw(8) << (int)byte[1] << endl;
   }
   return 0;
}

Both programs read in the binary data from test.dat and displayed (either to console or to form) the equivalent numerical data.

If everything you ever wanted to work with were an INI file, that'd be perfect. But if you want to make any sort of editor chances are you'll be using Binary file access.

How do I find the size of the file?
[edit] Nevermind. LOF(1) seems to be it.

I don't know what I am doing wrong, but I would like to be able to read and write to *.exe and *.dll files. The problem is that it only gets the header ( MZ ). Does anyone know what I may have done wrong, or another method that can open EXE and DLL files? Thanks!

-vivi0

I am having a trouble reading binary data

I have the following from the tutorial:

Quote:

Dim nFileNum As Integer, sString As String
nFileNum = FreeFile
Open "C:\Example\Example.txt" For Binary Access _
  Read Lock Read Write As #nFileNum
sString = Space$(6)
Get #nFileNum, 1, sString
Close #nFileNum
MsgBox sString

It reads the value in the file fine, but since i wrote the file in binary it reads it back in binary and all i get is a ""

Am i missing something... does the file need to be read in a certain way?

Hi. I'm having a similar problem, I just can't get the header. I want to check if a .BMP file is in the right format. The header is BM, but i'm just getting M8 as header. That must be wrong . How do you get the header? Isn't it just Code:

Get #FileNo, 2, sHeader

??

Never use 1 as file number. Use
Code:

Dim FileNo As Integer
FileNo = FreeFile
Open ... ... As #FileNo
Get #FileNo, , FileStr

[courier new]// Mathias[/courier new]