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- [/ Copyright 2005-2008 Daniel James.
- / Distributed under the Boost Software License, Version 1.0. (See accompanying
- / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
- [section:disable Disabling The Extensions]
- While [classref boost::hash]'s extensions are generally useful, you might want
- to turn them of in order to check that your code will work with other
- implementations of TR1. To do this define the macro `BOOST_HASH_NO_EXTENSIONS`.
- When this macro is defined, only the specialisations detailed
- in TR1 will be declared. But, if you later undefine the macro and include
- <[headerref boost/container_hash/hash.hpp]> then the non-specialised form will be defined
- - activating the extensions.
- It is strongly recommended that you never undefine the macro - and only define
- it so that it applies to the complete translation unit, either by defining it
- at the beginning of the main source file or, preferably, by using a compiler
- switch or preference. And you really should never define it in header files.
- If you are writing a library which has code in the header which requires the
- extensions, then the best action is to tell users not to define the macro.
- Their code won't ['require] the macro.
- Translation units that are compiled with the macro defined will link with units
- that were compiled without it. This feature has been designed to avoid ODR
- violations.
- [endsect]
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