Date: Sat, 21 May 2005 21:14:34 +0100 From: Bob Bishop <rb@gid.co.uk> To: Steve Kargl <sgk@troutmask.apl.washington.edu>, freebsd-standards@freebsd.org Subject: Re: Read /dev/null differs from POSIX Message-ID: <6.2.0.14.2.20050521211303.04837368@gid.co.uk> In-Reply-To: <20050521193605.GB51782@troutmask.apl.washington.edu> References: <20050521193605.GB51782@troutmask.apl.washington.edu>
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At 20:36 21/05/2005, Steve Kargl wrote: > >From http://www.opengroup.org/onlinepubs/009695399/toc.htm > > /dev/null -- An infinite data source and data sink. Data > written to /dev/null shall be discarded. Reads from > /dev/null shall always return end-of-file (EOF). > >This program > > #include <stdio.h> > int main(void) { > int i=0,j; > FILE *fp; > fp = fopen("/dev/null", "r"); > while(fread(&j, sizeof(int), 1, fp) != 1) { > i++; > if (i == 5) break; > } > printf("i = %d\n", i); > if (j == EOF) > printf("EOF\n"); > else > printf("j = %d\n", j); >} > >prints > >i = 5 >j = 1 > >Is this historic BSD defacto behavior? When fread hits EOF, it doesn't write to j. -- Bob Bishop +44 (0)118 940 1243 rb@gid.co.uk fax +44 (0)118 940 1295
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