Fixed so it doesn't trim any whitespace when converting, fixed reversed bad_lexical_cast constructor parameters, changed to pass-by-const reference

[SVN r29630]
This commit is contained in:
Terje Slettebø
2005-06-16 18:37:51 +00:00
parent 461dce3851
commit 7a388cb1a6

View File

@@ -196,28 +196,44 @@ public:
</blockquote>Exception used to indicate runtime <a href="#lexical_cast"><code>lexical_cast</code></a>
failure.
<hr>
<h2><a name="changes">Changes</a></h2>
<h3>June 2005:</h3>
<ul type="square">
<li>The previous version of <code>lexical_cast</code> used the default stream precision for reading
and writing floating-point numbers. For numerics that have a corresponding specialization of
<code>std::numeric_limits</code>, the current version now chooses a precision to match.
<li>The previous version of <code>lexical_cast</code> did not support conversion to or from any
wide-character-based types. For compilers with full language and library support for wide characters,
<code>lexical_cast</code> now supports conversions from <code>wchar_t</code>, <code>wchar_t *</code>,
and <code>std::wstring</code> and to <code>wchar_t</code> and <code>std::wstring</code>.
<li>The previous version of <code>lexical_cast</code> 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 <code>std::string</code> and, where supported, <code>std::wstring</code>:
<code>lexical_cast&lt;std::string&gt;("Hello, World")</code> succeeds instead of failing with
a <code>bad_lexical_cast</code> exception.
<li>The previous version of <code>lexical_cast</code> allowed unsafe and meaningless conversions to
pointers. The current version now throws a <code>bad_lexical_cast</code> for conversions to pointers:
<code>lexical_cast&lt;char *&gt;("Goodbye, World")</code> now throws an exception instead of
causing undefined behavior.
<li>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.<br>
</li>
<li>The MSVC 6 support is deprecated, and will be removed in a future Boost
version. </li>
</ul>
<h3>Earlier:</h3>
<ul type="square">
<li>The previous version of <code>lexical_cast</code> used the default stream
precision for reading and writing floating-point numbers. For numerics that
have a corresponding specialization of <code>std::numeric_limits</code>, the
current version now chooses a precision to match. <br>
<li>The previous version of <code>lexical_cast</code> did not support conversion
to or from any wide-character-based types. For compilers with full language
and library support for wide characters, <code>lexical_cast</code> now supports
conversions from <code>wchar_t</code>, <code>wchar_t *</code>, and <code>std::wstring</code>
and to <code>wchar_t</code> and <code>std::wstring</code>. <br>
<li>The previous version of <code>lexical_cast</code> 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 <code>std::string</code>
and, where supported, <code>std::wstring</code>: <code>lexical_cast&lt;std::string&gt;("Hello,
World")</code> succeeds instead of failing with a <code>bad_lexical_cast</code>
exception. <br>
<li>The previous version of <code>lexical_cast</code> allowed unsafe and meaningless
conversions to pointers. The current version now throws a <code>bad_lexical_cast</code>
for conversions to pointers: <code>lexical_cast&lt;char *&gt;("Goodbye, World")</code>
now throws an exception instead of causing undefined behavior.
</ul>
<p>
<hr>
<div align="right"><small><i>&copy; Copyright Kevlin Henney, 2000&#150;2003</i></small></div>
<div align="right"><small><i>&copy; Copyright Kevlin Henney, 2000&#150;2005</i></small></div>
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