_open generate "Access is denied" error

_Flaviu

I also tried this:

#include int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{

\_open("D:", 0x02 | 0x04);
UINT e = ::GetLastError();
cout << e;

}

from cmd line as administrator rights … the same result: 5 (access is denied).

Lost User

_Flaviu wrote:

this is the original code

From where?

leon de boer

Big Errors You can't open "D:" that isn't a file ... its not linux you don't mount drives Try

int nRespond = _open("D:\\somefilename.txt", _O_WRONLY | _O_CREAT);
UINT e = ::GetLastError();

I am sure it will open :-)

In vino veritas

_Flaviu

Agree. Is there any windows methods to open a disk and get the handle ? Because this nResponse it is used further as a handle ...

_Flaviu

I get this code from a plain C code which has built for Linux:

int nRespond = _open(device, 020);

Lost User

You cannot run Linux code on Windows without adjusting it for the differences. Windows does not let you address raw devices in the same way that Linux does. And in fact doing so is very dangerous as you could destroy your entire system.

_Flaviu

And is any other method to open a device rather than _open in Windows ? I think I have to made some changes into Linux code to run on Windows ...

Lost User

I gave you a link in my first message above which shows details of how to address devices in Windows. However, the real question is, what exactly are you trying to do?

Victor Nijegorodov

Yes. It is [CreateFile function (fileapi.h) | Microsoft Docs](https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea)

_Flaviu

Good idea. I have used CreateFileA, and I get rid of that "access denied". But there a thing that I had afraid: the original code, with _open returned int, and CreateFileA return HANDLE ... casting HANDLE to int is OK ? I guess not ...

Victor Nijegorodov

How are you going to use the handle returned from _open ?

leon de boer

Windows has GetLastError you notice CreateFile Simply returns invalid handle for an error if you get that then you call GetLastError GetLastError function (errhandlingapi.h) | Microsoft Docs[^] That is the equivalent of your original int it's just a non zero number identifying the error, 0 always equals no error.

In vino veritas