From: "James Kermode" <james DOT kermode AT usa DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: HELP: File-I/O under DJGPP ???
Date: Sat, 20 Feb 1999 01:03:35 -0000
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Hi,

If you use fopen() to open the file, rather than open() and save the result
in a FILE*, then you can move through the file using fseek()
eg:

  char some_char;
  FILE *fp;

  fp = fopen("myfile.pcx","rb");
  if (fp == NULL)
  {
    cout << "error";
    return 0;
  }
  fseek(fp,128,SEEK_SET); // go 128 bytes into file (ie skip the header)
  ....
  some_char = fgetc(f);
  ....
  fseek(fp,-768,SEEK_END); // skip back 768 bytes from the END of the file

I have written a PCX class if you are interested...

Hope this helps,
James Kermode

>I am writing a little class for loading .pcx-files and showing them on the
>screen.
>My problem is that I use the following code to open a .pcx-file and read it
>as follows:
>
>int handle;
>handle=open(name);
>if (handle<0) { cout<<"ERROR!"; exit(1); }
>
>Clear so far? I hope so, as this was just the opening of the file.
>
>I read it like this:
>
>int variable;
>read(handle, variable, sizeof(int));
>
>OK?
>
>My Problem now is that I need to change my position in the file (normally I
>use fseek or such a kind but here it doesn't work).
>What can I do to change my position?
>
>I really NEED help fast!
>
>Fozzie
>