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| author | DongHun Kwak <dh0128.kwak@samsung.com> | 2019-12-05 15:21:30 +0900 |
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| committer | DongHun Kwak <dh0128.kwak@samsung.com> | 2019-12-05 15:21:30 +0900 |
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diff --git a/doc/html/signals/tutorial.html b/doc/html/signals/tutorial.html deleted file mode 100644 index c4b31d3ffc..0000000000 --- a/doc/html/signals/tutorial.html +++ /dev/null @@ -1,1152 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Tutorial</title> -<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> -<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> -<link rel="up" href="../signals.html" title="Chapter 35. Boost.Signals"> -<link rel="prev" href="../signals.html" title="Chapter 35. Boost.Signals"> -<link rel="next" href="reference.html" title="Reference"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<table cellpadding="2" width="100%"><tr> -<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> -<td align="center"><a href="../../../index.html">Home</a></td> -<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> -<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> -<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> -<td align="center"><a href="../../../more/index.htm">More</a></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="../signals.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../signals.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> -</div> -<div class="section"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="signals.tutorial"></a>Tutorial</h2></div></div></div> -<div class="toc"><dl class="toc"> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.2">How to Read this Tutorial</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.3">Compatibility Note</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.4">Hello, World! (Beginner)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.5">Calling multiple slots</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.6">Passing values to and from slots</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7">Connection Management</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.8">Example: Document-View</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.9">Linking against the Signals library</a></span></dt> -</dl></div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.2"></a>How to Read this Tutorial</h3></div></div></div> -<p>This tutorial is not meant to be read linearly. Its top-level -structure roughly separates different concepts in the library -(e.g., handling calling multiple slots, passing values to and from -slots) and in each of these concepts the basic ideas are presented -first and then more complex uses of the library are described -later. Each of the sections is marked <span class="emphasis"><em>Beginner</em></span>, -<span class="emphasis"><em>Intermediate</em></span>, or <span class="emphasis"><em>Advanced</em></span> to help guide the -reader. The <span class="emphasis"><em>Beginner</em></span> sections include information that all -library users should know; one can make good use of the Signals -library after having read only the <span class="emphasis"><em>Beginner</em></span> sections. The -<span class="emphasis"><em>Intermediate</em></span> sections build on the <span class="emphasis"><em>Beginner</em></span> -sections with slightly more complex uses of the library. Finally, -the <span class="emphasis"><em>Advanced</em></span> sections detail very advanced uses of the -Signals library, that often require a solid working knowledge of -the <span class="emphasis"><em>Beginner</em></span> and <span class="emphasis"><em>Intermediate</em></span> topics; most users -will not need to read the <span class="emphasis"><em>Advanced</em></span> sections.</p> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.3"></a>Compatibility Note</h3></div></div></div> -<p>Boost.Signals has two syntactical forms: the preferred form and -the compatibility form. The preferred form fits more closely with the -C++ language and reduces the number of separate template parameters -that need to be considered, often improving readability; however, the -preferred form is not supported on all platforms due to compiler -bugs. The compatible form will work on all compilers supported by -Boost.Signals. Consult the table below to determine which syntactic -form to use for your compiler. Users of Boost.Function, please note -that the preferred syntactic form in Signals is equivalent to that of -Function's preferred syntactic form.</p> -<p>If your compiler does not appear in this list, please try the -preferred syntax and report your results to the Boost list so that -we can keep this table up-to-date.</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> - <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> -<li class="listitem"><p>GNU C++ 2.95.x, 3.0.x, 3.1.x</p></li> -<li class="listitem"><p>Comeau C++ 4.2.45.2</p></li> -<li class="listitem"><p>SGI MIPSpro 7.3.0</p></li> -<li class="listitem"><p>Intel C++ 5.0, 6.0</p></li> -<li class="listitem"><p>Compaq's cxx 6.2</p></li> -<li class="listitem"><p>Microsoft Visual C++ 7.1</p></li> -</ul></div> - </td> -<td align="left"> - <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> -<li class="listitem"><p><span class="emphasis"><em>Any compiler supporting the preferred syntax</em></span></p></li> -<li class="listitem"><p>Microsoft Visual C++ 6.0, 7.0</p></li> -<li class="listitem"><p>Borland C++ 5.5.1</p></li> -<li class="listitem"><p>Sun WorkShop 6 update 2 C++ 5.3</p></li> -<li class="listitem"><p>Metrowerks CodeWarrior 8.1</p></li> -</ul></div> - </td> -</tr></tbody> -</table></div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.4"></a>Hello, World! (Beginner)</h3></div></div></div> -<p>The following example writes "Hello, World!" using signals and -slots. First, we create a signal <code class="computeroutput">sig</code>, a signal that -takes no arguments and has a void return value. Next, we connect -the <code class="computeroutput">hello</code> function object to the signal using the -<code class="computeroutput">connect</code> method. Finally, use the signal -<code class="computeroutput">sig</code> like a function to call the slots, which in turns -invokes <code class="computeroutput">HelloWorld::operator()</code> to print "Hello, -World!".</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -struct HelloWorld -{ - void operator()() const - { - std::cout << "Hello, World!" << std::endl; - } -}; - -// ... - -// Signal with no arguments and a void return value -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><void ()> sig; - -// Connect a HelloWorld slot -HelloWorld hello; -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(hello); - -// Call all of the slots -sig(); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -struct HelloWorld -{ - void operator()() const - { - std::cout << "Hello, World!" << std::endl; - } -}; - -// ... - -// Signal with no arguments and a void return value -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal0</a></code><void> sig; - -// Connect a HelloWorld slot -HelloWorld hello; -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(hello); - -// Call all of the slots -sig(); -</pre> -</td> -</tr></tbody> -</table></div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.5"></a>Calling multiple slots</h3></div></div></div> -<div class="toc"><dl class="toc"> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.5.2">Connecting multiple slots (Beginner)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.5.3">Ordering slot call groups (Intermediate)</a></span></dt> -</dl></div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.5.2"></a>Connecting multiple slots (Beginner)</h4></div></div></div> -<p>Calling a single slot from a signal isn't very interesting, so -we can make the Hello, World program more interesting by splitting -the work of printing "Hello, World!" into two completely separate -slots. The first slot will print "Hello" and may look like -this:</p> -<pre class="programlisting"> -struct Hello -{ - void operator()() const - { - std::cout << "Hello"; - } -}; -</pre> -<p>The second slot will print ", World!" and a newline, to complete -the program. The second slot may look like this:</p> -<pre class="programlisting"> -struct World -{ - void operator()() const - { - std::cout << ", World!" << std::endl; - } -}; -</pre> -<p>Like in our previous example, we can create a signal -<code class="computeroutput">sig</code> that takes no arguments and has a -<code class="computeroutput">void</code> return value. This time, we connect both a -<code class="computeroutput">hello</code> and a <code class="computeroutput">world</code> slot to the same -signal, and when we call the signal both slots will be called.</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><void ()> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(Hello()); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(World()); - -sig(); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal0</a></code><void> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(Hello()); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(World()); - -sig(); -</pre> -</td> -</tr></tbody> -</table></div> -<p>By default, slots are called in first-in first-out (FIFO) order, -so the output of this program will be as expected:</p> -<pre class="programlisting"> -Hello, World! -</pre> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.5.3"></a>Ordering slot call groups (Intermediate)</h4></div></div></div> -<p>Slots are free to have side effects, and that can mean that some -slots will have to be called before others even if they are not connected in that order. The Boost.Signals -library allows slots to be placed into groups that are ordered in -some way. For our Hello, World program, we want "Hello" to be -printed before ", World!", so we put "Hello" into a group that must -be executed before the group that ", World!" is in. To do this, we -can supply an extra parameter at the beginning of the -<code class="computeroutput">connect</code> call that specifies the group. Group values -are, by default, <code class="computeroutput">int</code>s, and are ordered by the integer -< relation. Here's how we construct Hello, World:</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><void ()> sig; -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(1, World()); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(0, Hello()); -sig(); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal0</a></code><void> sig; -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(1, World()); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(0, Hello()); -sig(); -</pre> -</td> -</tr></tbody> -</table></div> -<p>This program will correctly print "Hello, World!", because the -<code class="computeroutput">Hello</code> object is in group 0, which precedes group 1 where -the <code class="computeroutput">World</code> object resides. The group -parameter is, in fact, optional. We omitted it in the first Hello, -World example because it was unnecessary when all of the slots are -independent. So what happens if we mix calls to connect that use the -group parameter and those that don't? The "unnamed" slots (i.e., those -that have been connected without specifying a group name) can be -placed at the front or back of the slot list (by passing -<code class="computeroutput">boost::signals::at_front</code> or <code class="computeroutput">boost::signals::at_back</code> -as the last parameter to <code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>, respectively), and defaults to the end of the list. When -a group is specified, the final parameter describes where the slot -will be placed within the group ordering. If we add a new slot -to our example like this:</p> -<pre class="programlisting"> -struct GoodMorning -{ - void operator()() const - { - std::cout << "... and good morning!" << std::endl; - } -}; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(GoodMorning()); -</pre> -<p>... we will get the result we wanted:</p> -<pre class="programlisting"> -Hello, World! -... and good morning! -</pre> -</div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.6"></a>Passing values to and from slots</h3></div></div></div> -<div class="toc"><dl class="toc"> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.6.2">Slot Arguments (Beginner)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.6.3">Signal Return Values (Advanced)</a></span></dt> -</dl></div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.6.2"></a>Slot Arguments (Beginner)</h4></div></div></div> -<p>Signals can propagate arguments to each of the slots they call. -For instance, a signal that propagates mouse motion events might -want to pass along the new mouse coordinates and whether the mouse -buttons are pressed.</p> -<p>As an example, we'll create a signal that passes two -<code class="computeroutput">float</code> arguments to its slots. Then we'll create a few -slots that print the results of various arithmetic operations on -these values.</p> -<pre class="programlisting"> -void print_sum(float x, float y) -{ - std::cout << "The sum is " << x+y << std::endl; -} - -void print_product(float x, float y) -{ - std::cout << "The product is " << x*y << std::endl; -} - -void print_difference(float x, float y) -{ - std::cout << "The difference is " << x-y << std::endl; -} - -void print_quotient(float x, float y) -{ - std::cout << "The quotient is " << x/y << std::endl; -} -</pre> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><void (float, float)> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_difference); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_quotient); - -sig(5, 3); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal2</a></code><void, float, float> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_difference); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&print_quotient); - -sig(5, 3); -</pre> -</td> -</tr></tbody> -</table></div> -<p>This program will print out the following:</p> -<pre class="programlisting"> -The sum is 8 -The product is 15 -The difference is 2 -The quotient is 1.66667 -</pre> -<p>So any values that are given to <code class="computeroutput">sig</code> when it is -called like a function are passed to each of the slots. We have to -declare the types of these values up front when we create the -signal. The type <code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a><void (float, -float)></code> means that the signal has a <code class="computeroutput">void</code> -return value and takes two <code class="computeroutput">float</code> values. Any slot -connected to <code class="computeroutput">sig</code> must therefore be able to take two -<code class="computeroutput">float</code> values.</p> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.6.3"></a>Signal Return Values (Advanced)</h4></div></div></div> -<p>Just as slots can receive arguments, they can also return -values. These values can then be returned back to the caller of the -signal through a <em class="firstterm">combiner</em>. The combiner is a mechanism -that can take the results of calling slots (there many be no -results or a hundred; we don't know until the program runs) and -coalesces them into a single result to be returned to the caller. -The single result is often a simple function of the results of the -slot calls: the result of the last slot call, the maximum value -returned by any slot, or a container of all of the results are some -possibilities.</p> -<p>We can modify our previous arithmetic operations example -slightly so that the slots all return the results of computing the -product, quotient, sum, or difference. Then the signal itself can -return a value based on these results to be printed:</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -float product(float x, float y) { return x*y; } -float quotient(float x, float y) { return x/y; } -float sum(float x, float y) { return x+y; } -float difference(float x, float y) { return x-y; } - -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><float (float x, float y)> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&quotient); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&difference); - -std::cout << sig(5, 3) << std::endl; -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -float product(float x, float y) { return x*y; } -float quotient(float x, float y) { return x/y; } -float sum(float x, float y) { return x+y; } -float difference(float x, float y) { return x-y; } - -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal2</a></code><float, float, float> sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&quotient); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&difference); - -std::cout << sig(5, 3) << std::endl; -</pre> -</td> -</tr></tbody> -</table></div> -<p>This example program will output <code class="computeroutput">2</code>. This is because the -default behavior of a signal that has a return type -(<code class="computeroutput">float</code>, the first template argument given to the -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code> class template) is to call all slots and -then return the result returned by the last slot called. This -behavior is admittedly silly for this example, because slots have -no side effects and the result is the last slot connect.</p> -<p>A more interesting signal result would be the maximum of the -values returned by any slot. To do this, we create a custom -combiner that looks like this:</p> -<pre class="programlisting"> -template<typename T> -struct maximum -{ - typedef T result_type; - - template<typename InputIterator> - T operator()(InputIterator first, InputIterator last) const - { - // If there are no slots to call, just return the - // default-constructed value - if (first == last) - return T(); - - T max_value = *first++; - while (first != last) { - if (max_value < *first) - max_value = *first; - ++first; - } - - return max_value; - } -}; -</pre> -<p>The <code class="computeroutput">maximum</code> class template acts as a function -object. Its result type is given by its template parameter, and -this is the type it expects to be computing the maximum based on -(e.g., <code class="computeroutput">maximum<float></code> would find the maximum -<code class="computeroutput">float</code> in a sequence of <code class="computeroutput">float</code>s). When a -<code class="computeroutput">maximum</code> object is invoked, it is given an input -iterator sequence <code class="computeroutput">[first, last)</code> that includes the -results of calling all of the slots. <code class="computeroutput">maximum</code> uses this -input iterator sequence to calculate the maximum element, and -returns that maximum value.</p> -<p>We actually use this new function object type by installing it -as a combiner for our signal. The combiner template argument -follows the signal's calling signature:</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><float (float x, float y), - maximum<float> > sig; -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal2</a></code><float, float, float, - maximum<float> > sig; -</pre> -</td> -</tr></tbody> -</table></div> -<p>Now we can connect slots that perform arithmetic functions and -use the signal:</p> -<pre class="programlisting"> -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&quotient); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&difference); - -std::cout << sig(5, 3) << std::endl; -</pre> -<p>The output of this program will be <code class="computeroutput">15</code>, because -regardless of the order in which the slots are connected, the product -of 5 and 3 will be larger than the quotient, sum, or -difference.</p> -<p>In other cases we might want to return all of the values -computed by the slots together, in one large data structure. This -is easily done with a different combiner:</p> -<pre class="programlisting"> -template<typename Container> -struct aggregate_values -{ - typedef Container result_type; - - template<typename InputIterator> - Container operator()(InputIterator first, InputIterator last) const - { - return Container(first, last); - } -}; -</pre> -<p> -Again, we can create a signal with this new combiner: -</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signal.html" title="Class template signal">boost::signal</a></code><float (float, float), - aggregate_values<std::vector<float> > > sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&quotient); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&difference); - -std::vector<float> results = sig(5, 3); -std::copy(results.begin(), results.end(), - std::ostream_iterator<float>(cout, " ")); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -<code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal2</a></code><float, float, float, - aggregate_values<std::vector<float> > > sig; - -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&quotient); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&product); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&sum); -sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(&difference); - -std::vector<float> results = sig(5, 3); -std::copy(results.begin(), results.end(), - std::ostream_iterator<float>(cout, " ")); -</pre> -</td> -</tr></tbody> -</table></div> -<p>The output of this program will contain 15, 8, 1.6667, and 2. It -is interesting here that -the first template argument for the <code class="computeroutput">signal</code> class, -<code class="computeroutput">float</code>, is not actually the return type of the signal. -Instead, it is the return type used by the connected slots and will -also be the <code class="computeroutput">value_type</code> of the input iterators passed -to the combiner. The combiner itself is a function object and its -<code class="computeroutput">result_type</code> member type becomes the return type of the -signal.</p> -<p>The input iterators passed to the combiner transform dereference -operations into slot calls. Combiners therefore have the option to -invoke only some slots until some particular criterion is met. For -instance, in a distributed computing system, the combiner may ask -each remote system whether it will handle the request. Only one -remote system needs to handle a particular request, so after a -remote system accepts the work we do not want to ask any other -remote systems to perform the same task. Such a combiner need only -check the value returned when dereferencing the iterator, and -return when the value is acceptable. The following combiner returns -the first non-NULL pointer to a <code class="computeroutput">FulfilledRequest</code> data -structure, without asking any later slots to fulfill the -request:</p> -<pre class="programlisting"> -struct DistributeRequest { - typedef FulfilledRequest* result_type; - - template<typename InputIterator> - result_type operator()(InputIterator first, InputIterator last) const - { - while (first != last) { - if (result_type fulfilled = *first) - return fulfilled; - ++first; - } - return 0; - } -}; -</pre> -</div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.7"></a>Connection Management</h3></div></div></div> -<div class="toc"><dl class="toc"> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.2">Disconnecting Slots (Beginner)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.3">Blocking Slots (Beginner)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.4">Scoped connections (Intermediate)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.5">Disconnecting equivalent slots (Intermediate)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.6">Automatic connection management (Intermediate)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.7">When can disconnections occur? (Intermediate)</a></span></dt> -<dt><span class="section"><a href="tutorial.html#id-1.3.36.4.7.8">Passing slots (Intermediate)</a></span></dt> -</dl></div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.2"></a>Disconnecting Slots (Beginner)</h4></div></div></div> -<p>Slots aren't expected to exist indefinately after they are -connected. Often slots are only used to receive a few events and -are then disconnected, and the programmer needs control to decide -when a slot should no longer be connected.</p> -<p>The entry point for managing connections explicitly is the -<code class="computeroutput"><a class="link" href="../boost/signals/connection.html" title="Class connection">boost::signals::connection</a></code> class. The -<code class="computeroutput"><a class="link" href="../boost/signals/connection.html" title="Class connection">connection</a></code> class uniquely represents the connection -between a particular signal and a particular slot. The -<code class="computeroutput"><a class="link" href="../boost/signals/connection.html#id-1_3_36_5_4_1_1_1_6_2-bb">connected</a>()</code> method checks if the signal and slot are -still connected, and the <code class="computeroutput"><a class="link" href="../boost/signals/connection.html#id-1_3_36_5_4_1_1_1_6_1-bb">disconnect()</a></code> method -disconnects the signal and slot if they are connected before it is -called. Each call to the signal's <code class="computeroutput">connect()</code> method -returns a connection object, which can be used to determine if the -connection still exists or to disconnect the signal and slot.</p> -<pre class="programlisting"> -boost::signals::connection c = sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(HelloWorld()); -if (c.<code class="computeroutput">connected</code>()) { -<span class="emphasis"><em>// c is still connected to the signal</em></span> - sig(); <span class="emphasis"><em>// Prints "Hello, World!"</em></span> -} - -c.disconnect(); <span class="emphasis"><em>// Disconnect the HelloWorld object</em></span> -assert(!c.<code class="computeroutput">connected</code>()); <span class="emphasis"><em>c isn't connected any more</em></span> - -sig(); <span class="emphasis"><em>// Does nothing: there are no connected slots</em></span> -</pre> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.3"></a>Blocking Slots (Beginner)</h4></div></div></div> -<p>Slots can be temporarily "blocked", meaning that they will be -ignored when the signal is invoked but have not been disconnected. The -<code class="computeroutput">block</code> member function -temporarily blocks a slot, which can be unblocked via -<code class="computeroutput">unblock</code>. Here is an example of -blocking/unblocking slots:</p> -<pre class="programlisting"> -boost::signals::connection c = sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(HelloWorld()); -sig(); <span class="emphasis"><em>// Prints "Hello, World!"</em></span> - -c.<code class="computeroutput">block</code>(); <span class="emphasis"><em>// block the slot</em></span> -assert(c.<code class="computeroutput">blocked</code>()); -sig(); <span class="emphasis"><em>// No output: the slot is blocked</em></span> - -c.<code class="computeroutput">unblock</code>(); <span class="emphasis"><em>// unblock the slot</em></span> -sig(); <span class="emphasis"><em>// Prints "Hello, World!"</em></span> -</pre> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.4"></a>Scoped connections (Intermediate)</h4></div></div></div> -<p>The <code class="computeroutput">boost::signals::scoped_connection</code> class -references a signal/slot connection that will be disconnected when -the <code class="computeroutput">scoped_connection</code> class goes out of scope. This -ability is useful when a connection need only be temporary, -e.g.,</p> -<pre class="programlisting"> -{ - boost::signals::scoped_connection c = sig.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(ShortLived()); - sig(); <span class="emphasis"><em>// will call ShortLived function object</em></span> -} -sig(); <span class="emphasis"><em>// ShortLived function object no longer connected to sig</em></span> -</pre> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.5"></a>Disconnecting equivalent slots (Intermediate)</h4></div></div></div> -<p>One can disconnect slots that are equivalent to a given function -object using a form of the -<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_2-bb">disconnect</a></code> method, so long as -the type of the function object has an accessible <code class="computeroutput">==</code> -operator. For instance: - -</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -void foo(); -void bar(); - -signal<void()> sig; - -sig.connect(&foo); -sig.connect(&bar); - -// disconnects foo, but not bar -sig.disconnect(&foo); -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -void foo(); -void bar(); - -signal0<void> sig; - -sig.connect(&foo); -sig.connect(&bar); - -// disconnects foo, but not bar -sig.disconnect(&foo); -</pre> -</td> -</tr></tbody> -</table></div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.6"></a>Automatic connection management (Intermediate)</h4></div></div></div> -<p>Boost.Signals can automatically track the lifetime of objects -involved in signal/slot connections, including automatic -disconnection of slots when objects involved in the slot call are -destroyed. For instance, consider a simple news delivery service, -where clients connect to a news provider that then sends news to -all connected clients as information arrives. The news delivery -service may be constructed like this: </p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -class NewsItem { /* ... */ }; - -boost::signal<void (const NewsItem&)> deliverNews; -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -class NewsItem { /* ... */ }; - -boost::signal1<void, const NewsItem&> deliverNews; -</pre> -</td> -</tr></tbody> -</table></div> -<p>Clients that wish to receive news updates need only connect a -function object that can receive news items to the -<code class="computeroutput">deliverNews</code> signal. For instance, we may have a -special message area in our application specifically for news, -e.g.,:</p> -<pre class="programlisting"> -struct NewsMessageArea : public MessageArea -{ -public: - // ... - - void displayNews(const NewsItem& news) const - { - messageText = news.text(); - update(); - } -}; - -// ... -NewsMessageArea newsMessageArea = new NewsMessageArea(/* ... */); -// ... -deliverNews.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(boost::bind(&NewsMessageArea::displayNews, - newsMessageArea, _1)); -</pre> -<p>However, what if the user closes the news message area, -destroying the <code class="computeroutput">newsMessageArea</code> object that -<code class="computeroutput">deliverNews</code> knows about? Most likely, a segmentation -fault will occur. However, with Boost.Signals one need only make -<code class="computeroutput">NewsMessageArea</code> <span class="emphasis"><em>trackable</em></span>, and the slot -involving <code class="computeroutput">newsMessageArea</code> will be disconnected when -<code class="computeroutput">newsMessageArea</code> is destroyed. The -<code class="computeroutput">NewsMessageArea</code> class is made trackable by deriving -publicly from the <code class="computeroutput">boost::signals::trackable</code> class, -e.g.:</p> -<pre class="programlisting"> -struct NewsMessageArea : public MessageArea, public boost::signals::trackable -{ - // ... -}; -</pre> -<p>At this time there is a significant limitation to the use of -<code class="computeroutput">trackable</code> objects in making slot connections: function -objects built using Boost.Bind are understood, such that pointers -or references to <code class="computeroutput">trackable</code> objects passed to -<code class="computeroutput">boost::bind</code> will be found and tracked.</p> -<p><span class="bold"><strong>Warning</strong></span>: User-defined function objects and function -objects from other libraries (e.g., Boost.Function or Boost.Lambda) -do not implement the required interfaces for <code class="computeroutput">trackable</code> -object detection, and <span class="emphasis"><em>will silently ignore any bound trackable -objects</em></span>. Future versions of the Boost libraries will address -this limitation.</p> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.7"></a>When can disconnections occur? (Intermediate)</h4></div></div></div> -<p>Signal/slot disconnections occur when any of these conditions -occur:</p> -<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> -<li class="listitem"><p>The connection is explicitly disconnected via the connection's -<code class="computeroutput">disconnect</code> method directly, or indirectly via the -signal's <code class="computeroutput">disconnect</code> method or -<code class="computeroutput">scoped_connection</code>'s destructor.</p></li> -<li class="listitem"><p>A <code class="computeroutput">trackable</code> object bound to the slot is -destroyed.</p></li> -<li class="listitem"><p>The signal is destroyed.</p></li> -</ul></div> -<p>These events can occur at any time without disrupting a signal's -calling sequence. If a signal/slot connection is disconnected at -any time during a signal's calling sequence, the calling sequence -will still continue but will not invoke the disconnected slot. -Additionally, a signal may be destroyed while it is in a calling -sequence, and which case it will complete its slot call sequence -but may not be accessed directly.</p> -<p>Signals may be invoked recursively (e.g., a signal A calls a -slot B that invokes signal A...). The disconnection behavior does -not change in the recursive case, except that the slot calling -sequence includes slot calls for all nested invocations of the -signal.</p> -</div> -<div class="section"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id-1.3.36.4.7.8"></a>Passing slots (Intermediate)</h4></div></div></div> -<p>Slots in the Boost.Signals library are created from arbitrary -function objects, and therefore have no fixed type. However, it is -commonplace to require that slots be passed through interfaces that -cannot be templates. Slots can be passed via the -<code class="computeroutput">slot_type</code> for each particular signal type and any -function object compatible with the signature of the signal can be -passed to a <code class="computeroutput">slot_type</code> parameter. For instance:</p> -<div class="informaltable"><table class="table"> -<colgroup> -<col> -<col> -</colgroup> -<thead><tr> -<th align="left">Preferred syntax</th> -<th align="left">Portable syntax</th> -</tr></thead> -<tbody><tr> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -class Button -{ - typedef boost::signal<void (int x, int y)> OnClick; - -public: - void doOnClick(const OnClick::slot_type& slot); - -private: - OnClick onClick; -}; - -void Button::doOnClick( - const OnClick::slot_type& slot - ) -{ - onClick.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(slot); -} - -void printCoordinates(long x, long y) -{ - std::cout << "(" << x << ", " << y << ")\n"; -} - -void f(Button& button) -{ - button.doOnClick(&printCoordinates); -} -</pre> -</td> -<td align="left"> -<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> -class Button -{ - typedef <code class="computeroutput"><a class="link" href="../boost/signalN.html" title="Class template signalN">boost::signal2</a></code><void,int,int> OnClick; - -public: - void doOnClick(const OnClick::slot_type& slot); - -private: - OnClick onClick; -}; - -void Button::doOnClick( - const OnClick::slot_type& slot - ) -{ - onClick.<code class="computeroutput"><a class="link" href="../boost/signalN.html#id-1_3_36_5_1_1_2_24_1-bb">connect</a></code>(slot); -} - -void printCoordinates(long x, long y) -{ - std::cout << "(" << x << ", " << y << ")\n"; -} - -void f(Button& button) -{ - button.doOnClick(&printCoordinates); -} -</pre> -</td> -</tr></tbody> -</table></div> -<p>The <code class="computeroutput">doOnClick</code> method is now functionally equivalent -to the <code class="computeroutput">connect</code> method of the <code class="computeroutput">onClick</code> -signal, but the details of the <code class="computeroutput">doOnClick</code> method can be -hidden in an implementation detail file.</p> -</div> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.8"></a>Example: Document-View</h3></div></div></div> -<p>Signals can be used to implement flexible Document-View - architectures. The document will contain a signal to which each of - the views can connect. The following <code class="computeroutput">Document</code> class - defines a simple text document that supports mulitple views. Note - that it stores a single signal to which all of the views will be - connected.</p> -<pre class="programlisting">class Document -{ -public: - typedef boost::signal<void (bool)> signal_t; - typedef boost::signals::connection connection_t; - -public: - Document() - {} - - connection_t connect(signal_t::slot_function_type subscriber) - { - return m_sig.connect(subscriber); - } - - void disconnect(connection_t subscriber) - { - subscriber.disconnect(); - } - - void append(const char* s) - { - m_text += s; - m_sig(true); - } - - const std::string& getText() const - { - return m_text; - } - -private: - signal_t m_sig; - std::string m_text; -};</pre> -<p>Next, we can define a <code class="computeroutput">View</code> base class from which - views can derive. This isn't strictly required, but it keeps the - Document-View logic separate from the logic itself. Note that the - constructor just connects the view to the document and the - destructor disconnects the view.</p> -<pre class="programlisting"> -class View -{ -public: - View(Document& m) - : m_document(m) - { - m_connection = m_document.connect(boost::bind(&View::refresh, this, _1)); - } - - virtual ~View() - { - m_document.disconnect(m_connection); - } - - virtual void refresh(bool bExtended) const = 0; - -protected: - Document& m_document; - -private: - Document::connection_t m_connection; -}; - </pre> -<p>Finally, we can begin to define views. The - following <code class="computeroutput">TextView</code> class provides a simple view of the - document text.</p> -<pre class="programlisting">class TextView : public View -{ -public: - TextView(Document& doc) - : View(doc) - {} - - virtual void refresh(bool bExtended) const - { - std::cout << "TextView: " << m_document.getText() << std::endl; - } -};</pre> -<p>Alternatively, we can provide a view of the document - translated into hex values using the <code class="computeroutput">HexView</code> - view:</p> -<pre class="programlisting">class HexView : public View -{ -public: - HexView(Document& doc) - : View(doc) - {} - - virtual void refresh(bool bExtended) const - { - const std::string& s = m_document.getText(); - - std::cout << "HexView:"; - - for (std::string::const_iterator it = s.begin(); it != s.end(); ++it) - std::cout << ' ' << std::hex << static_cast<int>(*it); - - std::cout << std::endl; - } -};</pre> -<p>To tie the example together, here is a - simple <code class="computeroutput">main</code> function that sets up two views and then - modifies the document:</p> -<pre class="programlisting">int main(int argc, char* argv[]) -{ - Document doc; - TextView v1(doc); - HexView v2(doc); - - doc.append(argc == 2 ? argv[1] : "Hello world!"); - return 0; -}</pre> -<p>The complete example source, contributed by Keith MacDonald, - is available in <a href="../../../libs/signals/example/doc_view.cpp" target="_top"><code class="computeroutput">libs/signals/example/doc_view.cpp</code></a>.</p> -</div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id-1.3.36.4.9"></a>Linking against the Signals library</h3></div></div></div> -<p>Part of the Boost.Signals library is compiled into a binary - library that must be linked into your application to use - Signals. Please refer to - the <a href="../../../more/getting_started.html" target="_top">Getting Started</a> - guide. You will need to link against the <code class="computeroutput">boost_signals</code> - library.</p> -</div> -</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 © 2001-2004 Douglas Gregor<p>Use, modification and distribution is subject to the Boost - Software License, Version 1.0. (See accompanying file - <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p> -</div></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="../signals.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../signals.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> -</div> -</body> -</html> |