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## Changes

- boost 1.48.0 :
  - Added code to work with Inf and NaN on any platform.
  - Better performance and less memory usage for conversions to float type (and to double type, if `sizeof(double) < sizeof(long double)`).
- boost 1.47.0 :
  - Optimizations for "C" and other locales without number grouping.
  - Better performance and less memory usage for unsigned char and signed char conversions.
  - Better performance and less memory usage for conversions to arithmetic types.
  - Better performance and less memory usage for conversions from arithmetic type to arithmetic type.
  - Directly construct Target from Source on some conversions (like conversions from string to string, from char array to string, from char to char and others).
- boost 1.34.0 :
  - Better performance for many combinations of Source and Target types. For more details refer to Alexander Nasonovs article Fine Tuning for lexical_cast, Overload #74, August 2006 (PDF).
- boost 1.33.0 :
  - Call-by-const reference for the parameters. This requires partial specialization of class templates, so it doesn't work for MSVC 6, and it uses the original pass by value there.
  - The MSVC 6 support is deprecated, and will be removed in a future Boost version.
- Earlier :
  - The previous version of lexical_cast used the default stream precision for reading and writing floating-point numbers. For numerics that have a corresponding specialization of `std::numeric_limits`, the current version now chooses a precision to match.
  - The previous version of lexical_cast did not support conversion to or from any wide-character-based types. For compilers with full language and library support for wide characters, `lexical_cast` now supports conversions from `wchar_t`, `wchar_t *`, and `std::wstring` and to `wchar_t` and `std::wstring`.
  - The previous version of `lexical_cast` assumed that the conventional stream extractor operators were sufficient for reading values. However, string I/O is asymmetric, with the result that spaces play the role of I/O separators rather than string content. The current version fixes this error for `std::string` and, where supported, `std::wstring`: `lexical_cast<std::string>("Hello, World")` succeeds instead of failing with a `bad_lexical_cast` exception.
  - The previous version of `lexical_cast` allowed unsafe and meaningless conversions to pointers. The current version now throws a `bad_lexical_cast` for conversions to pointers: `lexical_cast<char *>("Goodbye, World")` now throws an exception instead of causing undefined behavior.