Date: Wed, 21 Sep 2011 16:54:18 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: fsync bug
Message-ID: <20110921205418.GE31288@ednor.casa.cgf.cx>
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On Wed, Sep 21, 2011 at 02:43:21PM -0600, Eric Blake wrote:
>fsync() is required to work on read-only fds (in theory, you can sync 
>the atime metadata, which is a write operation triggered by a read-only 
>fd).  But cygwin rejects this program, which works on Linux:
>
>$ cat foo.c
>#include <errno.h>
>#include <unistd.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <assert.h>
>#include <fcntl.h>
>int main (void)
>{
>   int fd = open("file", O_CREAT|O_EXCL|O_WRONLY, 0600);
>   if (fd < 0)
>     return 1;
>   if (close(fd))
>     return 2;
>   fd = open("file", O_RDONLY);
>   if (fd < 0)
>     return 3;
>   if (fsync(fd))
>     return 4;
>   if (unlink("file"))
>     return 5;
>   puts("success");
>   return 0;
>}
>$ rm -f file && ./foo; echo $?
>4

http://msdn.microsoft.com/en-us/library/aa364439%28VS.85%29.aspx

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