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. Message-ID: <20000117014826.B389@hades.hell.gr> In-Reply-To: <20000115185839.4740.qmail@web113.yahoomail.com> References: <20000115185839.4740.qmail@web113.yahoomail.com>
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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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