Date: Thu, 20 Aug 2009 10:40:29 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
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Subject: Re: [ANNOUNCEMENT] Updated: run-1.1.11-1
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On Thu, Aug 20, 2009 at 07:07:21AM -0600, Eric Blake wrote:
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>Hash: SHA1
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>According to Dave Korn on 8/20/2009 7:11 AM:
>> Eric Blake wrote:
>> 
>>> See this thread on the gnulib list, which claims that you can use this
>>> undocumented snippet to decide whether a HANDLE is a console:
>>>
>>>> #define IsHandleConsole(h) (((long) (h) & 3) == 3)
>>> http://lists.gnu.org/archive/html/bug-gnulib/2009-08/msg00065.html
>> 
>>   I wouldn't rely on that for a microsecond.  The low two bits of a HANDLE are
>> pretty free form and could easily be used for other purposes by other types of
>> object.  Read the rest of the thread; it's a convention used internally by
>> WINE.  MS doesn't necessarily follow suit.
>
>Agreed - Bruno raised this concern, but Paolo committed the change anyway,
>so I've asked them to clarify.
>
>At any rate, Bruno also had this suggestion in that thread:
>
>static BOOL
>IsHandleConsole(HANDLE h)
>{
>  DWORD mode;
>  return GetConsoleMode (h, &mode);
>}

That should be even better than the Cygwin method, assuming that you don't
have to figure out if the handle is opened for input or output.

cgf

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