file length

how do you get the length of a file after you open it with fopen?

tried a search but it gave me about 600pages

Code:

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    // open file
    fp = fopen( szFileName, "rb");
        if(!fp)
            return 1; //error       
   
    // get the length
    fp_length = _filelength((int)fp);    //doesnt work. not made for FILE*

---

ifstream infile("somefile.ext", ios :: in | ios :: binary);

infile.seekg(0, ios :: end);

int filesize = infile.tellg();


a very recently learned trick :)

thx for the help

Code:

---

    // open file
    fp = fopen( szFileName, "rb");
        if(!fp)
            return 1; //error       
   
    // get the length
    fseek(fp, 0, SEEK_END); //move pointer to the end of file
    fp_length = ftell(fp);  //pointer now == filelen
    fseek(fp, 0, SEEK_SET); //move pointer to the start of the file

---

Quote:

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from msdn
The value returned by ftell may not reflect the physical byte offset for streams opened in text mode, because text mode causes carriage return–linefeed translation.

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if your using this you need to open the file for binary reading.

You can always use a platform specific utility, and cover it up with a uniform interface. For UNIX/Linux, you'd use 'stat'... not sure about Windows.

Quote:

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Originally posted by Zach L.
You can always use a platform specific utility, and cover it up with a uniform interface. For UNIX/Linux, you'd use 'stat'... not sure about Windows.

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OR, you could just go with the standard way and not have to worry about portability.

Apparently, using SEEK_END with fseek for text files is undefined: http://cboard.cprogramming.com/showt...ighlight=fseek
With that in mind, i'd say your best bet would be to use to use GetFileSize() / GetFileSizeEx() on Windows, or, as Zach said stat() on UNIX/Linux.

both GetFileSize() / GetFileSizeEx() reqquire file handles from CreateFile().
in using fopen() which returns a FILE*. thats y i couldnt find anything on the msdn cd

>>Apparently, using SEEK_END with fseek for text files is undefined:
Just to clarify, "text files" are simply those that aren't opened in binary mode. If you do use binary mode, you should be OK, no matter what contents your file has.

That said, I still agree, a implementation specific routine would be a better way to go. You can always hide it behind a generic function anyway to make it more portable.

I think stat is implemented in VC++'s CRT too.