Re: [Various] libc/1616: core dump after changing buffer using setvbuf

[Andreas Jaeger <aj at suse dot de>]

>>>>> Andreas Schwab writes:

 > Andreas Jaeger <aj@suse.de> writes:
 > |> Hi glibc folks,
 > |> 
 > |> we've received the appended bug report together with a patch that
 > |> should fix the problem.
 > |> 
 > |> Could somebody please check whether the fix is correct?  Ulrich told
 > |> me privatly that he thinks the problem should be elsewhere.

 > That's correct.

 > \begin{quote}[C9x-draft, 7.19.5.6]
 >        [#2] The setvbuf function may be used only after the  stream
 >        pointed  to  by stream has been associated with an open file
 >        and before any other operation (other than  an  unsuccessful
 >        call  to  setvbuf) is performed on the stream.
 > \end{quote}

 > The program invokes undefined behaviour.

Thanks.  In this case the man page is wrong since it states[1]:

       The  setvbuf  function may be used at any time on any open
       stream to change its buffer.  The mode parameter  must  be
       one of the following three macros:

We should also document this in our manual.  Andreas, can you provide
a patch.

Andreas

Footnotes: 
[1]  I'll take care of the manpages.
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.rhein-neckar.de