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X-Authentication-Warning: slinky.cs.nyu.edu: pechtcha owned process doing -bs
Date: Tue, 10 Dec 2002 14:45:52 -0500 (EST)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: "Pierre A. Humblet" <pierre DOT humblet AT ieee DOT org>
cc: cygwin AT cygwin DOT com
Subject: Re: cygwin 1.3.17-1 gethostbyname() leak
In-Reply-To: <20021210192244.GA250329@WORLDNET>
Message-ID: <Pine.GSO.4.44.0212101444100.12239-100000@slinky.cs.nyu.edu>
Importance: Normal
MIME-Version: 1.0
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Pierre,

Corinna's earlier post indicated that using this pointer collided with
Cygwin's fork/exec mechanism...
	Igor

On Tue, 10 Dec 2002, Pierre A. Humblet wrote:

> On Wed, Dec 11, 2002 at 06:12:21AM +1100, Noel Gordon wrote:
>
> > If it is true that cygwin uses gethostbyname() from wsock32.dll, and
> > returns the wsock32.dll hostent* result to the application, then it
> > is perhaps unwise to free() it. Following your tip, we find from ...
> >
>
> In net.cc cygwin takes the result from the MS GetHostByName and copies
> it to its own calloc'ed structure.
> Not sure why, given that the MS function already returns a pointer to
> a per thread structure, as indicated below.
>
> Pierre
>
> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/winsock/gethostby
> > name_2.asp
> >
> >   Remarks
> >
> >   The gethostbyname function returns a pointer to a hostent structure - a
> >   structure allocated by Windows Sockets. The hostent structure contains
> >   the results of a successful search for the host specified in the name
> >   parameter [of gethostbyname()].
> >
> >   The application must never attempt to modify this structure or to free
> >   any of its components. Furthermore, only one copy of this structure is
> >   allocated per thread, so the application should copy any information it
> >   needs before issuing any other Windows Sockets function calls.
> >

-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_		pechtcha AT cs DOT nyu DOT edu
ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"Water molecules expand as they grow warmer" (C) Popular Science, Oct'02, p.51



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