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Date:      Thu, 07 Aug 2008 16:46:37 +0200
From:      Gabor Kovesdan <gabor@kovesdan.org>
To:        hackers@FreeBSD.org
Cc:        fjoe@FreeBSD.org
Subject:   strange issue reading /dev/null
Message-ID:  <489B0ACD.80008@kovesdan.org>
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Hello,

I'm wondering why fgetc() returns 0xff if called with /dev/null:

#include <stdio.h>
#include <stdlib.h>

int
main(void)
{
        int      c;
        FILE    *f;

        f = fopen("/dev/null", "r");

        if (c != EOF)
                printf("%c\n", fgetc(f));
}

 > gcc foo.c
 > ./a.out
˙

This causes a bug in BSD grep as /dev/null is not distinguished from 
ordinary files in the code, thus I was expecting it just returned EOF, 
but in reality this is not the case. How such cases should be handled?

Thanks in advance,
Gábor

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