Advanced File I/O questions

[Kevin Perez]

Hello Everyone,

I am currently having difficulty understanding File I/O. In one line of code I open an output file in binary mode. In the very next line I check to see if the file is open. What would prevent the file from opening? I know that is_open function returns false if the bad and/or fail bit(s) are set, but no documentation I have read shows an example of how these bits are set.
If someone can show me an example, I would appreciate it. I believe if the computer has 0 bytes left on the hard drive, that would cause opening a new file to fail, but that is only one of at least two scenarios where opening a file would fail.

Thank you,

Kevin

[Banfa]

The most common cause for a file to fail to open is that it does not exist. Either there has been a typo in the name of the file or the directory is wrong.

Other problems could be a sharing issue, another program already has the file open in a way that prevents your program opening it.

Or may be the disk could be corrupted in a way that prevents it opening.

[donbock]

Are you checking if the file opened successfully by looking at the value returned by open/fopen or are you calling a separate is_open function?

Whoops! As Banfa explains in the next message, this comment makes no sense for C++. Never mind.

[Banfa]

Don this is C++, is_open is a member function of fstream/ifstream/ofstream so the return value of open/fopen doesn't really come into it.

[Kevin Perez]

In my program, I working solely from the console prompt. This program is similar to notepad. It allows the user to choose between creating a new file, opening the file, and/or editing the file. If the user chooses to edit a non-existent file, should I then give them the choice to create a file?