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Date: Mon, 17 Jan 2000 01:48:26 +0200
From: Giorgos Keramidas <charon@hades.hell.gr>
To: Carlos Maracabay <caradusa@yahoo.com>
Cc: freebsd-questions@FreeBSD.ORG
Subject: Re: Language C on Freebsd Release 3.3 Question.
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On Sat, Jan 15, 2000 at 10:58:39AM -0800, Carlos Maracabay wrote:
> Hi!
> 
> I have problems making a simple program that opens
> a file, to view it contents on the monitor scream...
> what's the problem in this source file, to do this, in
> Freebsd??
> 
> Any help will be appreciated.
> Thanks for your time!
> 
>                             Regards,
>                                    Dimetriov.
> #include <stdio.h>
> #include <fcntl.h>
> #include <sys/types.h>
> #include <unistd.h>
>  
>  
> 
>  
> main(int argc, char *argv[])
> {
> 
> int f1,n;
> char buf[BUFSIZ];
> 
> if(argc != 2)
>   printf("Argument meesing\n");
> if(f1 = open(argv[1], O_RDONLY,0) == -1)

The above statement, bearing in mind that == will happen first, will be
equivalent to the fully parenthesized:

  if (f1 = (open(argv[1], O_RDONLY, 0) == -1))

which depending on whether open() succeeds or not, will always set f1
to C's notion of true or false, either 1 or 0 respectively.  You can
bet that you'll be reading from the wrong descriptor if this happens,
since both 0 and 1 are descriptors already assigned to standard input
and standard output ;)

> printf("cp cant open \n");
        __^^__

I surely hope you're not calling your executable `cp' with /bin/cp in
your PATH before the current directory... and expect to call your
program without a leading ./ as in:

	% ./cp FILE

Ciao.

-- 
Giorgos Keramidas, < keramida @ ceid . upatras . gr >
"What we have to learn to do, we learn by doing." [Aristotle]


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