C / C++ / MFC

Re: Why can't i read from a cd-rom drive when i have opened it with CreateFIle?

15-Jun-02 11:59

ok, this is my code:

char *s = (char *)malloc(1024);
DWORD dwBytesRead;
HANDLE hFile;

hFile = CreateFile("\\\\.\\D:", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
ReadFile(hFile, s, 1024, &dwBytesRead, NULL);

CloseHandle(hFile);
free(s);

D is my CD drive, but when i do this, the ReadFile function returns 1 indicating the operation went succesful. bu the dwBytesRead is 0 and the buffer hasn't been filled. however if i change the "\\\\.\\D:" to ("\\\\.\\C:", then it works fine, anyone know what's wrong?

thanks in advance

JohnnyG15-Jun-02 12:17

JohnnyG

15-Jun-02 12:17

I don't have the answer to your question but I don't think you want FILE_SHARE_WRITE on a read-only device.

Re: Why can't i read from a cd-rom drive when i have opened it with CreateFIle?

redeemer15-Jun-02 12:22

Re: Why can't i read from a cd-rom drive when i have opened it with CreateFIle?

15-Jun-02 12:22

I know, but it can't hurt, can it?

Amit Dey15-Jun-02 14:24

Re: Why can't i read from a cd-rom drive when i have opened it with CreateFIle?

15-Jun-02 14:24

sonork: 100:18407

You yard yellow years yieldingly; you yanked your yearning yoke.

-Jeremy Falcon

Amit Dey15-Jun-02 14:22

15-Jun-02 14:22

Here's some code to help you out.

void CCDReadDlg::ReadCD()
{
DWORD dwSize = 2048;
DWORD dwBytesRead;
LPBYTE lpBuffer;
HANDLE hFile;
hFile = CreateFile("\\\\.\\F:", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile != INVALID_HANDLE_VALUE)
{
lpBuffer =(unsigned char*) VirtualAlloc (NULL, dwSize,
MEM_COMMIT|MEM_RESERVE,
PAGE_READWRITE);
//In CDFS(i.e.ISO9660 format) sector size is 2048.
//the first 16 sectors are always filled with 0's
//To get something meaningful first skip to 16th sector and then read
//course the propah way is to first use DeviceIoControl calls
//to lock the media and finally unlock it after reading... Smile | :)

.
SetFilePointer (hFile, dwSize*16,
NULL, FILE_BEGIN);
if (ReadFile (hFile, lpBuffer, dwSize, &dwBytesRead, NULL))
{
//you buffer should have a volume descriptor
//to begin with

//do something
}
VirtualFree (lpBuffer, 0, MEM_RELEASE);

}
CloseHandle(hFile);
}

sonork: 100:18407

You yard yellow years yieldingly; you yanked your yearning yoke.

-Jeremy Falcon

strange...

redeemer15-Jun-02 14:43

15-Jun-02 14:43

dwBytesRead is 0 and lpBuffer is empty. But the ReadFile function returns 1 so there shouldn't be anything wrong... strange

Re: strange...

Amit Dey15-Jun-02 15:07

15-Jun-02 15:07

dwBytesRead is 2048 for me(with media present in CDROM ofcourse) i.e. 1 sector(just what I want) and lpBuffer contains the CDROM volume description as expected.

You yard yellow years yieldingly; you yanked your yearning yoke.-Jeremy Falcon-CPite.

Amit Dey

sonork: 100:18407
msn: visualcdev

Re: strange...

Amit Dey15-Jun-02 15:12

15-Jun-02 15:12

Is your CDROM drive setup correctly? Do you have any other cdfs drivers like Adaptec DirectCD on your system? course, you are trying this code on Win2K/NT...right?

hmmm....

You yard yellow years yieldingly; you yanked your yearning yoke.-Jeremy Falcon-CPite.

Amit Dey

sonork: 100:18407
msn: visualcdev

toolbar on desktop

slah15-Jun-02 11:16

slah

15-Jun-02 11:16

HI i want to have a toolbar on desktop, but CreateToolbarEx()
needs a window handle as a parent. I have passed the desktop handle by calling GetDesktopWindow but it doesn't work. Is there any solution to the problem.

Re: toolbar on desktop

Amit Dey15-Jun-02 11:58

Re: DataBase via Internet

15-Jun-02 11:58

You'd want to use an appbar. Please lookup codeproject for an article and code on appbars.

sonork: 100:18407

You yard yellow years yieldingly; you yanked your yearning yoke.

-Jeremy Falcon

DataBase via Internet

laphijia15-Jun-02 7:24

laphijia

15-Jun-02 7:24

I made a Visual C++ application that uses ADO to query a database, and to update the changes.
I send some simple SQL statement to the database (an Access DB until now), like SELECT, UPDATE, etc.

Now I would like to make this through the internet.
I mean I run my program on my computer and it query the database that instead is on another computer, and it connects to it via tha Internet.

Where I can find a guide on how to do it?
Thankyou.

P.S.
I also think that I will need to use SQL Server or Oracle to store my database remotely, ad than use this server. Are there any service that offers this kind of hosting for free, so that I can start experimenting, without the hassle of installing my own SQL Server or ORACLE ?

Thank you very much.

"Nelle cose del mondo non e' il sapere ma il volere che puo'."

Jason Henderson15-Jun-02 7:44

Jason Henderson

15-Jun-02 7:44

You can do this any number of ways.
Here is how we currently do it at work:

Create an XML file on the client describing the data.
Send the XML to an ASP page which then passes it on to a COM object.
The COM object parses the entire XML and adds the data to the db.
You could also use an ISAPI DLL to parse the data.
(BTW, you need to have IIS running on the computer you are sending to.)

Jason Henderson
_{quasi-homepage}
^articles
_{"Like it or not, I'm right!"}

How to make a button usable when a for statement is running. (Non-MFC)

redeemer15-Jun-02 6:58

Re: How to make a button usable when a for statement is running. (Non-MFC)

15-Jun-02 6:58

If i have a function that uses a for loop that does very much and the action could take up to 5 minutes. How do i, if i have a cancel button on the form, make that cancel button usable? Cause i can't use it while the for loop is running. I saw something in the faq about multithreading but i don't know how to use it.

Thanks in advance.

Jason Henderson15-Jun-02 7:49

Jason Henderson

15-Jun-02 7:49

I think this will work:

void Yield()
{
   MSG msg;
   if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
   {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
   }
}

for ...
{
   // your code
   Yield();
}

Jason Henderson
_{quasi-homepage}
^articles
_{"Like it or not, I'm right!"}

Re: How to make a button usable when a for statement is running. (Non-MFC)

redeemer15-Jun-02 8:29

Writing a filesystem driver?

15-Jun-02 8:29

Thankyou, works perfectly.

clintsinger15-Jun-02 6:16

clintsinger

15-Jun-02 6:16

Hi all,

I want to make a file system driver to access BeOS partitions from windows 2000. I am having a hard time learning how to get access to the partition info and how to mount a drive so that I can then access the foreign file system.

I guess after I am successfull in mounting a drive (including all the code to read and write) I will need to make it a shell extension so that it shows up transparently in Explorer? Is that right?

Any pointers to tutorials, source code, etc. would be greatly appreciated.

Cheers,
Clint

Amit Dey15-Jun-02 12:00

15-Jun-02 12:00

I think you will find open source filesystem drivers for NTFS,ext2(Linux) at sourceforge.net very illuminating.There are a couple of Beos ports to NTFS drivers too(I think).

sonork: 100:18407

You yard yellow years yieldingly; you yanked your yearning yoke.

-Jeremy Falcon

Mike Nordell16-Jun-02 5:27

Mike Nordell

16-Jun-02 5:27

Then you're in for a treat. Not!

MS has the FSD SDK for $5k (or is it perhaps $10k+ nowadays?) with no support, sparse documentation and no promises they won't change everything behind your back even from service-pack to service-pack, making this one of the "great developer experiences" that MS loves to force down our throats with a rough 2-by-4 without any K-Y.

Good luck, I really think you need it.

I guess after I am successfull in mounting a drive (including all the code to read and write) I will need to make it a shell extension so that it shows up transparently in Explorer? Is that right?

No. Once you have the filesystem mounted it's just like any other filesystem (except that you can't use half of the features in BFS on this DOS-emulation platform). You perhaps could get access to the attributes using the NT-only syntax for alternate file streams "filename:stream_name", but since you'd be the only one using it (since it's incompatible with everything except NTFS almost no-one ever uses it) you'd (obviously) have to write your own programs to access that too.

The only place I can point you to is http://ntfsd.org

++luck;

clintsinger16-Jun-02 13:21

clintsinger

16-Jun-02 13:21

Thanks for you information. I am too poor to afford anything so I guess the FSD SDK is out of the question.

One thing I would like clarification on is about the dos-emulation layer you mentioned. I am aware that there is an emulation layer but are you saying I could write a driver for dos and use it to access another filesystem from within win2k?

Thanks again,
Clint

Mike Nordell17-Jun-02 17:49

Mike Nordell

17-Jun-02 17:49

One thing I would like clarification on is about the dos-emulation layer you mentioned.

I forgot to add the <sarcasm> tag. I was referring to the fact that Win32 is little more than MS-DOS with longer filenames when it comes to filesystem and filename handling.
I'm sorry if it got your hopes up.