std::ifstream question

This is a discussion on std::ifstream question within the C++ Programming forums, part of the General Programming Boards category; I would like to respond to a failure of not being able to open a file by trying to open ...

  1. #1
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    std::ifstream question

    I would like to respond to a failure of not being able to open a file by trying to open a different file, but it seems like if you fail once you're going to fail again even if you try to open a file that is really there:

    Code:
    std::ifstream f;
    	f.open(filename.c_str());
    
    	if(f.fail())
    	{
    		// do something appropriate
    		f.close();
    		f.open("data\\setpieces\\24x24_1_0_0.txt");
    	}
    
    // f will fail again even though the file I'm trying to open is really there
    Is there some way of revalidating the f object?

  2. #2
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    f.clear()

    The stream object has error flags that get set when there is a problem. They stay set until you clear() them.

  3. #3
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    wow what a fast responce. I'll have to come here more often. Thanks.

  4. #4
    Devil's Advocate SlyMaelstrom's Avatar
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    Quote Originally Posted by psyadam
    Is there some way of revalidating the f object?
    Since you understand the logic of it being an object, you might also understand that the failed state is simply a Boolean member that's been flagged false. Calling the close() method doesn't flip that flag back.
    Sent from my iPadŽ

  5. #5
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    f.clear() did the trick. Thanks, i didn't see that function documented on msdn.microsoft.com

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