Messages in this thread | | | Date | Wed, 7 Jun 2006 06:52:19 +0530 | From | "vamsi krishna" <> | Subject | Re: Quick close of all the open files. |
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> > > > > I checked as follows I did printf("lowest fd = %d",fileno(tmpfile())); > > it prints 3 > > Which proves that file descriptor 3 was closed, so tmpfile() was able to > open it. This certainly implies that fd 0, 1, 2 (connected to stdin, > stdout, and stderr streams of stdio) are still open, contrary to your > statement that *all* of them are closed.
I know 0,1,2 are open (I opened it) no need to tell it specifically, HOW DO YOU THINK I CAN PRINT SOME THING WITHOUT OPENING THIS FILES(stdout,stderr)?
> > If file descriptor 3 is closed, but 4 is open, what does tmpfile() > do? Hint - tmpfile() ends up invoking open(), and the manpage for that says: > > Given a pathname for a file, open() returns a file descriptor, a small, > non-negative integer for use in subsequent system calls (read(2), > write(2), lseek(2), fcntl(2), etc.). The file descriptor returned by a > successful call will be the lowest-numbered file descriptor not cur- > rently open for the process. > > So.. explain why you think that "all files were closed"? We know that 0..2 > were open, and we know nothing about 4..1023. > > This doesn't look like a kernel bug, you may want to continue the discussion > on one of the various "beginning Linux C programming" lists. > > On Tue, 06 Jun 2006 23:03:38 BST, =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= said: > > > (Hint - what does that fp->_chain = stderr *really* do? ;) > > > > As it touches the innards of the FILE type, it invokes undefined > > behavior. Nothing that follows can be considered a bug. > > Invoking undefined behavior is often considered a bug itself. And it's > certainly happening in userspace.. so there's a userspace bug. ;) > > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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