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From: Terry Lambert <terry@lambert.org>
Message-Id: <199605022027.NAA12665@phaeton.artisoft.com>
Subject: Re: stdio problem
To: jmacd@deceit.xcf.berkeley.edu (Josh MacDonald)
Date: Thu, 2 May 1996 13:27:16 -0700 (MST)
Cc: freebsd-hackers@FreeBSD.org
In-Reply-To: <199605020858.BAA05189@deceit.xcf.berkeley.edu> from "Josh MacDonald" at May 2, 96 01:58:26 am
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> In the following code:
> 
> #include <stdlib.h>
> #include <stdio.h>
> 
> int main(int argc, char** argv)
> {
>   if(argc != 2) {
>     fprintf(stderr, "no\n");
>     exit(1);
>   }
> 
>   close(0);
>   if(!freopen(argv[1], "r", stdin)) {
>     perror("freopen");
>     exit(1);
>   }
>   while(fgetc(stdin) != EOF) { }
>   if(ferror(stdin)) {
>     perror("stdin");
>     exit(1);
>   }
>   printf("its okay\n");
>   exit(0);
> }
> 
> FreeBSD exits "stdin: Bad file descriptor"
> Linux, SunOS, ULTRIX, PTX, Solaris, HP-UX, IRIX, etc... all report
> "its okay".  
> 
> I am wondering if either FreeBSD, the rest of the OS's, or no one
> is "wrong".  The pracical application here is that if you close 0
> and then exec GNU diff3 you'll encounter this problem.  Is it legal
> to close your standard input and then fork/exec other programs?  
> I was under the impression that is was.  Am I defying the laws of
> physics if I close(0) and then fork/exec a program expecting to 
> maybe use its standard input with freopen?  I don't think so.

What is argument 1 to the program?


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.