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From: Bob Friesenhahn <bfriesen@simple.dallas.tx.us>
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Cc: TIFF mailing list <tiff@lists.maptools.org>
Subject: Re: [Tiff] Proposed API improvements
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On Tue, 5 Jul 2016, Olivier Paquet wrote:

> 2016-07-05 11:41 GMT-04:00 Bob Friesenhahn <bfriesen@simple.dallas.tx.us>:
>
>> when it is introduced.  A concern would be that most using applications are
>> already written, existing applications still need to work with many existing
>> libtiff versions, and so the new interface would not be used.
>
> While I agree uptake will likely be very slow and limited, by that
> argument, we'd never improve anything.

Update will be faster if there is a compelling reason to use a new 
interface.

>> to those functions.  There is the possibility of using thread specific data
>> to avoid this approach, but this assumes that the thread which registers the
>> error callbacks is the same as will be later using libtiff functions which
>> need to call this error handler.  I have some thread specific data API
>
> A bad assumption to make in my experience. Besides, this doesn't fix
> the problem with multiple competing error handlers in different parts
> of a single threaded application. Binding the error handler to a TIFF
> handle would fix it and requires no knowledge of threads.

Right, making assumptions and changing compilation requirements is 
bad.

Binding the error handler to a TIFF handle will fix the issue except 
for the case where there is not yet a TIFF handle.

Bob
-- 
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
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