From:	Nate Eldredge <neldredge AT hmc DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: DJGPP & CGI, I found an easier way!
Date:	26 Mar 2000 12:59:37 -0800
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Robin Johnson <robbat2 AT home DOT com> writes:

> No, your idea has the same flaw as the type command, to get
> functionality like cat you should use the following instead:
> 
> open file as binary;
> test if exist;

This automatically gets done by the open.

> get file size;
> while (current position < size)

I don't think this part is a good idea, or even necessary.  Not all
files have sizes (think devices like con, com1), and even ordinary
files may grow or shrink while you're reading them.  It is sufficient
just to open in binary mode, and stop when EOF is returned.  EOF is
different from every character (including ^Z) so this is safe.

>  { get character from file;
>    if (character <> eof)
>     		output to STDOUT
>     else don't output it 
>    }
> end program;

So I would write:

int c;
FILE *f = fopen(filename, "rb");
if (!f)
        handle_error();
while ((c=getc(f)) != EOF)
        putc(f, stdout);
if (ferror(f))
        handle_error();

It might be interesting to read the source for cat, and to see all the
weird stuff that they do, and why.  (See also GNU Hello for more of
the same ;-)

-- 

Nate Eldredge
neldredge AT hmc DOT edu

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