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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/boost/libs/functional/index.html | |
parent | Initial commit. (diff) | |
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Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/boost/libs/functional/index.html')
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1 files changed, 263 insertions, 0 deletions
diff --git a/src/boost/libs/functional/index.html b/src/boost/libs/functional/index.html new file mode 100644 index 000000000..f4315a0ba --- /dev/null +++ b/src/boost/libs/functional/index.html @@ -0,0 +1,263 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> + +<html> +<head> + <meta http-equiv="Content-Language" content="en-us"> + <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <meta name="GENERATOR" content="Microsoft FrontPage 6.0"> + <meta name="ProgId" content="FrontPage.Editor.Document"> + + <title>Boost Function Object Adapter Library</title> +</head> + +<body bgcolor="#FFFFFF" text="#000000"> + <table border="1" bgcolor="#007F7F" cellpadding="2" summary=""> + <tr> + <td bgcolor="#FFFFFF"><img src="../../boost.png" alt= + "boost.png (6897 bytes)" width="277" height="86"></td> + + <td><a href="../../index.htm"><font face="Arial" color= + "#FFFFFF"><big>Home</big></font></a></td> + + <td><a href="../libraries.htm"><font face="Arial" color= + "#FFFFFF"><big>Libraries</big></font></a></td> + + <td><a href="http://www.boost.org/people/people.htm"><font face="Arial" color= + "#FFFFFF"><big>People</big></font></a></td> + + <td><a href="http://www.boost.org/more/faq.htm"><font face="Arial" color= + "#FFFFFF"><big>FAQ</big></font></a></td> + + <td><a href="../../more/index.htm"><font face="Arial" color= + "#FFFFFF"><big>More</big></font></a></td> + </tr> + </table> + + <h1>Improved Function Object Adapters</h1> + + <p>The header <a href="../../boost/functional.hpp">functional.hpp</a> + provides enhancements to the function object adapters specified in the C++ + Standard Library (sections 20.3.5, through to 20.3.8). The enhancements are + principally possible due to two changes:</p> + + <ol> + <li>We use the Boost <tt><a href= + "../utility/call_traits.htm">call_traits</a></tt> templates to avoid the + problem of <a href="binders.html#refref">references to references</a>, + and to improve the efficiency of <a href="mem_fun.html#args">parameter + passing</a>.</li> + + <li>We use two <a href="function_traits.html">function object traits</a> + class templates to avoid the need for <tt><a href= + "ptr_fun.html">ptr_fun</a></tt> with the adapters in this library.</li> + </ol> + + <h3>Contents</h3> + + <p>The header contains the following function and class templates:</p> + + <table border="1" cellpadding="5" summary=""> + <tr> + <th align="left"><a href="function_traits.html">Function object + traits</a></th> + + <td valign="top"><tt>unary_traits<br> + binary_traits</tt></td> + + <td valign="top">Used to determine the types of function objects' and + functions' arguments. Eliminate the necessity for + <tt>ptr_fun</tt>.</td> + </tr> + + <tr> + <th align="left"><a href="negators.html">Negators</a></th> + + <td valign="top"><tt>unary_negate<br> + binary_negate<br> + not1<br> + not2</tt></td> + + <td valign="top">Based on section 20.3.5 of the standard.</td> + </tr> + + <tr> + <th align="left"><a href="binders.html">Binders</a></th> + + <td valign="top"><tt>binder1st<br> + binder2nd<br> + bind1st<br> + bind2nd</tt></td> + + <td valign="top">Based on section 20.3.6 of the standard.</td> + </tr> + + <tr> + <th align="left"><a href="ptr_fun.html">Adapters for pointers to + functions</a></th> + + <td valign="top"><tt>pointer_to_unary_function<br> + pointer_to_binary_function<br> + ptr_fun</tt></td> + + <td valign="top">Based on section 20.3.7 of the standard. Not required + for use with this library since the binders and negators can adapt + functions, but may be needed with third party adapters.</td> + </tr> + + <tr> + <th align="left"><a href="mem_fun.html">Adapters for pointers to member + functions</a></th> + + <td valign="top"><tt>mem_fun_t<br> + mem_fun1_t<br> + const_mem_fun_t<br> + const_mem_fun1_t<br> + mem_fun_ref_t<br> + mem_fun1_ref_t<br> + const_mem_fun_ref_t<br> + const_mem_fun1_ref_t<br> + mem_fun<br> + mem_fun_ref</tt></td> + + <td valign="top">Based on section 20.3.8 of the standard.</td> + </tr> + </table> + + <h3>Usage</h3> + + <p>Using these adapters should be pretty much the same as using the + standard function object adapters; the only differences are that you need + to write <tt>boost::</tt> instead of <tt>std::</tt>, and that you will get + fewer headaches.</p> + + <p>For example, suppose you had a <tt>Person</tt> class that contained a + <tt>set_name</tt> function:</p> + + <blockquote> + <pre> +class Person +{ + public: + void set_name(const std::string &name); + // ... +}; +</pre> + </blockquote> + + <p>You could rename a bunch of people in a collection, <tt>c</tt>, by + writing</p> + + <blockquote> + <pre> +std::for_each(c.begin(), c.end(), + boost::bind2nd(boost::mem_fun_ref(&Person::set_name), "Fred")); +</pre> + </blockquote> + + <p>If the standard adapters had been used instead then this code would + normally fail to compile, because <tt>set_name</tt> takes a reference + argument. Refer to the comments in the <a href="binders.html#refref">binder + documentation</a> to explain why this is so.</p> + + <h3>Compiler Compatibility</h3> + + <p>The header and <a href="test/function_test.cpp">test program</a> have been + compiled with the following compilers:</p> + + <table border="1" cellpadding="5" summary=""> + <tr> + <th>Compiler</th> + + <th>Comments</th> + </tr> + + <tr> + <td valign="top">Borland C++Builder 4 Update 2</td> + + <td valign="top">No known issues.</td> + </tr> + + <tr> + <td valign="top">Borland C++ 5.5</td> + + <td valign="top">No known issues.</td> + </tr> + + <tr> + <td valign="top">g++ 2.95.2</td> + + <td valign="top">No known issues.</td> + </tr> + + <tr> + <td valign="top">Microsoft Visual C++ Service Pack 3</td> + + <td valign="top"> + Compiler lacks partial specialisation, so this library offers little + more than is provided by the standard adapters: + + <ul> + <li>The <tt>call_traits</tt> mechanism is unable to prevent + references to references, and so the adapters in this library will + be usable in fewer situations.</li> + + <li>The <tt>function_traits</tt> mechanism is unable to determine + the argument and result types of functions, therefore + <tt>ptr_fun</tt> continues to be required to adapt functions.</li> + </ul> + </td> + </tr> + </table> + + <h3>Future Directions</h3> + + <p>This library's primary focus is to solve the problem of references to + references while maintaining as much compatibility as possible with the + standard library. This allows you to use the techniques you read about in + books and magazines with many of today's compilers.</p> + + <p>In the longer term, even better solutions are likely:</p> + + <ol> + <li>Several Boost members are working on expression template libraries. + These will allow a more natural syntax for combining and adapting + functions. As this is a new technology, it may be some time before it has + matured and is widely supported by major compilers but shows great + promise. In the meantime, the functional.hpp library fills the gap.</li> + + <li>The Standard Committee has recognised the problem of references to + references occurring during template instantiation and has moved to fix + the standard (see the <a href= + "http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#106">C++ + standard core language active issues list</a>).</li> + </ol> + + <h3>Author</h3> + + <p><a href="http://www.boost.org/people/mark_rodgers.htm">Mark Rodgers</a></p> + + <h3>Acknowledgements</h3> + + <p>Thanks to <a href="http://www.boost.org/people/john_maddock.htm">John Maddock</a> for + suggesting the mechanism that allowed the function objects traits to work + correctly. <a href="http://www.boost.org/people/jens_maurer.htm">Jens Maurer</a> provided + invaluable feedback during the <a href= + "http://www.boost.org/more/formal_review_process.htm">formal review process</a>.</p> + <hr> + + <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src= + "../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional" + height="31" width="88"></a></p> + + <p>Revised + <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->02 + December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38510" --></p> + + <p><i>Copyright © 2000 Cadenza New Zealand Ltd.</i></p> + + <p><i>Distributed under the Boost Software License, Version 1.0. (See + accompanying file <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or + copy at <a href= + "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> +</body> +</html> |