Subject: [Boost-commit] svn:boost r64779 - sandbox/chrono/libs/chrono/doc/html/boost_chrono/overview
From: vicente.botet_at_[hidden]
Date: 2010-08-13 04:18:41
Author: viboes
Date: 2010-08-13 04:18:40 EDT (Fri, 13 Aug 2010)
New Revision: 64779
URL: http://svn.boost.org/trac/boost/changeset/64779
Log:
Update doc
Added:
sandbox/chrono/libs/chrono/doc/html/boost_chrono/overview/description.html (contents, props changed)
Added: sandbox/chrono/libs/chrono/doc/html/boost_chrono/overview/description.html
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+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<title>Description</title>
+<link rel="stylesheet" href="../../../../../../doc/html/boostbook.css" type="text/css">
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+<link rel="start" href="../../index.html" title="Boost.Chrono">
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+</div>
+<div class="section" lang="en">
+<div class="titlepage"><div><div><h3 class="title">
+<a name="boost_chrono.overview.description"></a>Description
+</h3></div></div></div>
+<p>
+ The <span class="bold"><strong>Boost.Chrono</strong></span> library provides:
+ </p>
+<div class="itemizedlist"><ul type="disc">
+<li>
+ A means to represent time durations: managed by the generic <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code></a> class . Examples of time
+ durations include <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration_typedefs" title="
+ duration typedefs"><code class="computeroutput"><span class="identifier">days</span></code></a>, <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration_typedefs" title="
+ duration typedefs"><code class="computeroutput"><span class="identifier">minutes</span></code></a>, <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration_typedefs" title="
+ duration typedefs"><code class="computeroutput"><span class="identifier">seconds</span></code></a> and <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration_typedefs" title="
+ duration typedefs"><code class="computeroutput"><span class="identifier">nanoseconds</span></code></a>, which can be represented
+ with a fixed number of clock ticks per unit. All of these units of time
+ duration are united with a generic interface by the <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code></a> facility.
+ </li>
+<li>
+ A type for representing points in time: <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a>. A <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a> represents an epoch
+ plus or minus a <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code></a>. The library leaves epochs
+ unspecified. A <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a> is associated with
+ a <span class="emphasis"><em>clock</em></span>.
+ </li>
+<li>
+ Several clocks, some of which may not be available on a particular platform:
+ <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.system_clock" title="
+ Class system_clock"><code class="computeroutput"><span class="identifier">system_clock</span></code></a>, <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.monotonic_clock" title="
+ Class monotonic_clock"><code class="computeroutput"><span class="identifier">monotonic_clock</span></code></a> and <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.high_resolution_clock" title="
+ Class high_resolution_clock"><code class="computeroutput"><span class="identifier">high_resolution_clock</span></code></a>. A clock
+ is a pairing of a <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a> and <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code></a>, and a function which
+ returns a <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a> representing <span class="emphasis"><em>now</em></span>.
+ </li>
+</ul></div>
+<p>
+ Additionally, a minimal amount of general purpose infrastructure is provided
+ which will support both the interface and implementation of the <span class="emphasis"><em>clocks</em></span>,
+ <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code>'s</a> and <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code>'s</a> proposed herein. It is
+ expected that these general purpose facilities will also find utility in
+ far ranging user applications as well.
+ </p>
+<div class="itemizedlist"><ul type="disc">
+<li>
+<a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.common_type_hpp.common_type" title="
+ Class Template common_type<>"><code class="computeroutput"><span class="identifier">common_type</span></code></a> is a traits class
+ used to deduce a type common to a several types, useful as the return type
+ of functions operating on multiple input types such as in mixed-mode arithmetic.
+ </li>
+<li>
+ A class template, <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.ratio_hpp.ratio" title=" Class
+ Template ratio<>"><code class="computeroutput"><span class="identifier">ratio</span></code></a>, for specifying compile
+ time rational constants such as 1/3 of a nanosecond or the number of inches
+ per meter. <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.ratio_hpp.ratio" title=" Class
+ Template ratio<>"><code class="computeroutput"><span class="identifier">ratio</span></code></a> represents a compile time
+ ratio of compile time constants with support for compile time arithmetic
+ with overflow and division by zero protection
+ </li>
+</ul></div>
+<p>
+ Knowing how long a program takes to execute is useful in both test and production
+ environments. On top of the standard facilities <span class="bold"><strong>Boost.Chrono</strong></span>
+ includes:
+ </p>
+<div class="itemizedlist"><ul type="disc">
+<li>
+ Stopwatches: A facility to measure elapsed time with the ability to start,
+ stop, suspend, or resume measurement.
+ <div class="itemizedlist"><ul type="circle">
+<li>
+<a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_req" title="
+ Stopwatch Requirements"><code class="computeroutput"><span class="identifier">Stopwatch</span></code></a> concept
+ </li>
+<li>
+ Scoped helper classes allowing to pairwise start/stop operations, suspend/resume
+ and resume/suspend a <a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_req" title="
+ Stopwatch Requirements"><code class="computeroutput"><span class="identifier">Stopwatch</span></code></a>.
+ </li>
+<li>
+<a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_hpp.stopwatch" title="
+ Template Class stopwatch<>"><code class="computeroutput"><span class="identifier">stopwatch</span></code></a>, model of <a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_req" title="
+ Stopwatch Requirements"><code class="computeroutput"><span class="identifier">Stopwatch</span></code></a> capturing elapsed
+ <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.clock" title="
+ Clock Requirements"><code class="computeroutput"><span class="identifier">Clock</span></code></a> times.
+ </li>
+<li>
+<a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_accumulator_hpp.stopwatch_accumulator" title="
+ Template Class stopwatch_accumulator<>"><code class="computeroutput"><span class="identifier">stopwatch_accumulator</span></code></a>, model
+ of <a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_req" title="
+ Stopwatch Requirements"><code class="computeroutput"><span class="identifier">Stopwatch</span></code></a> capturing cummulated
+ elapsed Clock times.
+ </li>
+</ul></div>
+</li>
+<li>
+ a Stopclocks higher layer: provide a complete stopclock reporting package
+ that can be invoked in a single line of code.
+ <div class="itemizedlist"><ul type="circle">
+<li>
+<a href="../reference/reporters.html#boost_chrono.reference.reporters.stopwatch_reporter_hpp.stopwatch_reporter" title="
+ Template Class stopwatch_reporter<>"><code class="computeroutput"><span class="identifier">stopwatch_reporter</span></code></a>, convenient
+ reporting to an output stream (including wide char streams) of the
+ elapsed time of models of <a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_req" title="
+ Stopwatch Requirements"><code class="computeroutput"><span class="identifier">Stopwatch</span></code></a> results.
+ </li>
+<li>
+<a href="../reference/reporters.html#boost_chrono.reference.reporters.stopclock_hpp.stopclock" title="
+ Template Class stopclock<>"><code class="computeroutput"><span class="identifier">stopclock</span><span class="special"><</span><span class="identifier">Clock</span><span class="special">></span></code></a>
+ shortcut of <code class="computeroutput"><a href="../reference/reporters.html#boost_chrono.reference.reporters.stopwatch_reporter_hpp.stopwatch_reporter" title="
+ Template Class stopwatch_reporter<>"><code class="computeroutput"><span class="identifier">stopwatch_reporter</span></code></a><span class="special"><</span><a href="../reference/stopwatches.html#boost_chrono.reference.stopwatches.stopwatch_hpp.stopwatch" title="
+ Template Class stopwatch<>"><code class="computeroutput"><span class="identifier">stopwatch</span></code></a><span class="special"><</span><span class="identifier">Clock</span><span class="special">>></span></code>
+</li>
+</ul></div>
+</li>
+</ul></div>
+<p>
+ To make the timing facilities more generally useful, <span class="bold"><strong>Boost.Chrono</strong></span>
+ provides a number of clocks that are thin wrappers around the operating system's
+ time APIs, thereby allowing the extraction of read (wall clock) time, user
+ CPU time, system CPU time,
+ </p>
+<div class="itemizedlist"><ul type="disc">
+<li>
+<a href="../reference/other_clocks.html#boost_chrono.reference.other_clocks.process_cpu_clocks_hpp.process_real_cpu_clock" title="
+ Class process_real_cpu_clock"><code class="computeroutput"><span class="identifier">process_real_cpu_clock</span></code></a>, captures
+ real (wall clock) CPU times.
+ </li>
+<li>
+<a href="../reference/other_clocks.html#boost_chrono.reference.other_clocks.process_cpu_clocks_hpp.process_user_cpu_clock" title="
+ Class process_user_cpu_clock"><code class="computeroutput"><span class="identifier">process_user_cpu_clock</span></code></a>, captures
+ user-CPU times.
+ </li>
+<li>
+<a href="../reference/other_clocks.html#boost_chrono.reference.other_clocks.process_cpu_clocks_hpp.process_system_cpu_clock" title="
+ Class process_system_cpu_clock"><code class="computeroutput"><span class="identifier">process_system_cpu_clock</span></code></a>, captures
+ system-CPU times.
+ </li>
+<li>
+ A tuple-like class <code class="computeroutput"><span class="identifier">process_cpu_clock</span></code>,
+ that captures real, user-CPU, and system-CPU times together.
+ </li>
+<li>
+ Thread clocks, when supported by a platform.
+ </li>
+</ul></div>
+<p>
+ Lastly, <span class="bold"><strong>Boost.Chrono</strong></span> includes typeof
+ registration for <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.duration" title="
+ Class template duration<>"><code class="computeroutput"><span class="identifier">duration</span></code></a> and <a href="../reference/cpp0x.html#boost_chrono.reference.cpp0x.chrono_chrono_hpp.time_point" title="
+ Class template time_point<>"><code class="computeroutput"><span class="identifier">time_point</span></code></a> to permit using emulated
+ auto with C++03 compilers.
+ </p>
+<a name="boost_chrono.overview.description.caveat_emptor"></a><h4>
+<a name="id4758927"></a>
+ Caveat emptor
+ </h4>
+<p>
+ The underlying clocks provided by operating systems are subject to many seemingly
+ arbitrary policies and implementation irregularities. That's a polite way
+ of saying they tend to be flakey, and each operating system or even each
+ clock has its own cruel and unusual forms of flakiness. Don't bet the farm
+ on their accuracy, unless you have become deeply familiar with exactly what
+ the specific operating system is guaranteeing, which is often very little.
+ </p>
+</div>
+<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
+<td align="left"></td>
+<td align="right"><div class="copyright-footer">Copyright © 2008 Howard Hinnant<br>Copyright © 2006 , 2008 Beman Dawes<br>Copyright © 2009 -2010 Vicente J. Botet Escriba<p>
+ 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)
+ </p>
+</div></td>
+</tr></table>
+<hr>
+<div class="spirit-nav">
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