How to check whether the file is already open?

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1.00/5 (1 vote)

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I have used this statements to open the file
CStdioFile readFile;

C++

if(readFile.Open(strFilePath, CFile::modeRead,&fileException))
{
  ...
}

if its already opened i get warning How to check whether the file is already opened?

second time when i try to open the same file I should close the file and read again from first.

Posted 7-Mar-12 21:44pm

chaiein

Updated 7-Mar-12 22:15pm

v3

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chaiein 8-Mar-12 22:02pm

econd time when i try to open the same file i should close the file and read again from first.How to do ??

3 solutions

Solution 1

The Open method should nicely handle such a scenario, that is: the method failure (together with the exception) is a test to see if the file is already open.

Posted 7-Mar-12 21:51pm

CPallini

Comments

chaiein 8-Mar-12 3:54am

But i try to open already opened file exactly near the open statement i am getting Assertion Failure warning. How to solve this problem?

chaiein 8-Mar-12 4:05am

ya.second time when i try to open the same file i should close the file and read again from first.

chaiein 8-Mar-12 4:14am

Is there any other way to read a file similar to above without causing problem when i try to open file

Solution 3

As the debugger showed a protected member of CFile::m_strFileName became empty for the closed file.
So, derive your class from CFile and add a function

bool MyFile::isClosed () const {return m_strFileName.IsEmpty ();}

Posted 8-Apr-24 10:11am

Vasily Androshchook

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chaiein · Accepted Answer · 2012-03-14T00:57:00

Solution 2

I have solve this problem to find whether the file is open or closed by using a variable of boolean type.

C++

if(closed==false)
{
	readFile.Close();
	closed=true;	
	
}

and before opening a file

C++

if(closed==true)
{
    if (readFile.Open(strFilePath, CFile::modeRead, &fileException))
    {
      closed=false;
      {
        }
    }
}

when ever closed make true when ever opened make false

Posted 14-Mar-12 0:57am

chaiein

Comments

Jochen Arndt 14-Mar-12 7:06am

So your question is: How to check if the CStdioFile is opened?

You don't need to track it yourself. See CFile::hFileNull [^]

chaiein 14-Mar-12 7:38am

thanks for the reply I solved my problem using above solution :)