_open generate "Access is denied" error - C / C++ / MFC Discussion Boards

_Flaviu13-Sep-19 1:13

13-Sep-19 1:13

You can use CListCtrl or derivated to display db data.

In search box you can test the user input with is_digit[^] and act accordingly (if is number then use ID to get data, or if is not number, use string to get the name and so on.

Re: MFC vc++ and MySQL database

Member 1457555615-Sep-19 19:33

Member 14575556

15-Sep-19 19:33

Thank you for always helping. I really appreciate the help Smile | :)

I have created a search function and now it's displaying in the CListCtrl and working the way I wanted. Smile | :)

I'll try to extend the functionality like if I select the result in the CListCtrl it will take me to another dialog that contains the details of the selected. Smile | :)

If I have any doubt i'll post it here.

Thanks again Smile | :)

Re: MFC vc++ and MySQL database

_Flaviu15-Sep-19 22:30

_Flaviu

15-Sep-19 22:30

You are welcome Smile | :)

Re: MFC vc++ and MySQL database

Member 1457555616-Sep-19 3:06

Member 14575556

16-Sep-19 3:06

Hello I'm back again Big Grin | :-D

How to get all the data present in a row displayed in the ListCtrl from the database and display those data in the next dialog?

For example:- There are name, age,dob..etc in a row.. when I select this row and press the select button.. It will take me to another where all this details will be display.

If you don't mind could you please give example.

Thanks.

Re: MFC vc++ and MySQL database

_Flaviu16-Sep-19 8:05

_Flaviu

16-Sep-19 8:05

Then you take all your list control data with CListCtrl::GetItemText[^] and you simply put them into next dialog, just like that:

C++

CNextDlg dlg;
dlg.m_sName = m_ListCtrl.GetItemText(...);
dlg.m_sAge = m_ListCtrl.GetItemText(...);
dlg.m_sDOB = m_ListCtrl.GetItemText(...);
dlg.DoModal();

Re: MFC vc++ and MySQL database

Member 1457555617-Sep-19 20:29

Member 14575556

17-Sep-19 20:29

Thank you.

C++

void CMyDlg::ResetListControl() {
	m_ListControl.DeleteAllItems();
	int iNbrOfColumns;
	CHeaderCtrl* pHeader = (CHeaderCtrl*)m_ListControl.GetDlgItem(0);
	if (pHeader) {
		iNbrOfColumns = pHeader->GetItemCount();
	}
	for (int i = iNbrOfColumns; i >= 0; i--) {
		m_ListControl.DeleteColumn(i);
	}
}

I particularly don't understand this line :

C++

CHeaderCtrl* pHeader = (CHeaderCtrl*)m_ListControl.GetDlgItem(0);

Could you please explain this line of code. Thanks Smile | :)

Re: MFC vc++ and MySQL database

_Flaviu18-Sep-19 1:10

_Flaviu

18-Sep-19 1:10

I think that line should be:

C++

CHeaderCtrl* pHeader = m_ListControl.GetHeaderCtrl();

See here[^].

However, that line retrieve first control item from m_ListCtrl object ... does working that line ? I didn't met such approach ...

_open generate "Access is denied" error

_Flaviu1-Sep-19 7:44

_Flaviu

1-Sep-19 7:44

Confidence that I have solved all strange errors here, I come back with some issue generated by a legacy C code for linux, code that I intend to use it in a MFC app in windows OS.

Ok. I have a simple code:

C++

int nRespond = _open(device, 020);
UINT err = ::GetLastError();

where devide is const char* and has value C (or D:, or E: )
The nRespond is -1 and err has value 5, which is mean Access is denied. What could be the problem here ? I ran the test app as administrator mode (ran from VS2017 as admin mode).

Re: _open generate "Access is denied" error

Graham Breach1-Sep-19 21:04

Graham Breach

1-Sep-19 21:04

The problem appears to be that you are expecting Linux code to work on Windows. The _open function opens a file - on unix systems you can open directories and devices as files, but not on Windows.

If you're lucky the code is actually expecting a normal file and you just passed in a device letter by mistake. Otherwise you will have to port the code, replacing the Linux system functions with code that does the same thing on Windows.

Re: _open generate "Access is denied" error

Richard MacCutchan1-Sep-19 22:04

Richard MacCutchan

1-Sep-19 22:04

You cannot access raw devices on Windows by their drive letters, you must use their volume identifiers. See File path formats on Windows systems | Microsoft Docs[^].

Re: _open generate "Access is denied" error

_Flaviu2-Sep-19 1:58

_Flaviu

2-Sep-19 1:58

So I cannot open disk with this function ? ... this is the original code ... strange ...

Re: _open generate "Access is denied" error

Richard MacCutchan2-Sep-19 5:42

Richard MacCutchan

2-Sep-19 5:42

_Flaviu wrote:
this is the original code

From where?

Re: _open generate "Access is denied" error

_Flaviu4-Sep-19 0:30

_Flaviu

4-Sep-19 0:30

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

C++

int nRespond = _open(device, 020);

Re: _open generate "Access is denied" error

Richard MacCutchan4-Sep-19 1:10

Richard MacCutchan

4-Sep-19 1:10

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.

Re: _open generate "Access is denied" error

_Flaviu4-Sep-19 1:18

_Flaviu

4-Sep-19 1:18

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 ...

modified 4-Sep-19 7:31am.

Re: _open generate "Access is denied" error

Richard MacCutchan4-Sep-19 1:31

Richard MacCutchan

4-Sep-19 1:31

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?

Re: _open generate "Access is denied" error

leon de boer1-Sep-19 22:19

leon de boer

1-Sep-19 22:19

Your flags (020) are linux flags not windows try ( _O_WRONLY | _O_CREAT ) or some normal windows flags

_open, _wopen | Microsoft Docs[^]

I would add even in linux the code really should be written as flags not a value like that for this exact reason.

In vino veritas

modified 2-Sep-19 4:33am.

Re: _open generate "Access is denied" error

_Flaviu2-Sep-19 1:37

_Flaviu

2-Sep-19 1:37

I have tried this:

C++

int nRespond = _open(device, _O_WRONLY | _O_CREAT);
UINT e = ::GetLastError();

with the same result (error 5). Strange ....

Re: _open generate "Access is denied" error

_Flaviu2-Sep-19 3:27

_Flaviu

2-Sep-19 3:27

I also tried this:

C++

#include <io.h>

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).

Re: _open generate "Access is denied" error

leon de boer2-Sep-19 14:52

leon de boer

2-Sep-19 14:52

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 Smile | :)

In vino veritas

Re: _open generate "Access is denied" error

_Flaviu4-Sep-19 0:29

_Flaviu

4-Sep-19 0:29

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

Re: _open generate "Access is denied" error

Victor Nijegorodov4-Sep-19 1:58

Victor Nijegorodov

4-Sep-19 1:58

Yes. It is CreateFile function (fileapi.h) | Microsoft Docs

Re: _open generate "Access is denied" error

_Flaviu4-Sep-19 9:01

_Flaviu

4-Sep-19 9:01

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 ...

Re: _open generate "Access is denied" error

Victor Nijegorodov4-Sep-19 9:09

Victor Nijegorodov

4-Sep-19 9:09

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

Re: _open generate "Access is denied" error

leon de boer4-Sep-19 15:03

leon de boer

4-Sep-19 15:03

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

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