Sophie: octave-doc-0:5.1.0-7.1.mga7 noarch

octave-doc-5.1.0-7.1.mga7.noarch.rpm

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Function Handles (GNU Octave (version 5.1.0))</title>

<meta name="description" content="Function Handles (GNU Octave (version 5.1.0))">
<meta name="keywords" content="Function Handles (GNU Octave (version 5.1.0))">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html#Top" rel="start" title="Top">
<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Function-Handles-Anonymous-Functions-Inline-Functions.html#Function-Handles-Anonymous-Functions-Inline-Functions" rel="up" title="Function Handles Anonymous Functions Inline Functions">
<link href="Anonymous-Functions.html#Anonymous-Functions" rel="next" title="Anonymous Functions">
<link href="Function-Handles-Anonymous-Functions-Inline-Functions.html#Function-Handles-Anonymous-Functions-Inline-Functions" rel="prev" title="Function Handles Anonymous Functions Inline Functions">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>
<link rel="stylesheet" type="text/css" href="octave.css">


</head>

<body lang="en">
<a name="Function-Handles"></a>
<div class="header">
<p>
Next: <a href="Anonymous-Functions.html#Anonymous-Functions" accesskey="n" rel="next">Anonymous Functions</a>, Up: <a href="Function-Handles-Anonymous-Functions-Inline-Functions.html#Function-Handles-Anonymous-Functions-Inline-Functions" accesskey="u" rel="up">Function Handles Anonymous Functions Inline Functions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Function-Handles-1"></a>
<h4 class="subsection">11.11.1 Function Handles</h4>

<p>A function handle is a pointer to another function and is defined with
the syntax
</p>
<div class="example">
<pre class="example">@<var>function-name</var>
</pre></div>

<p>For example,
</p>
<div class="example">
<pre class="example">f = @sin;
</pre></div>

<p>creates a function handle called <code>f</code> that refers to the
function <code>sin</code>.
</p>
<p>Function handles are used to call other functions indirectly, or to pass
a function as an argument to another function like <code>quad</code> or
<code>fsolve</code>.  For example:
</p>
<div class="example">
<pre class="example">f = @sin;
quad (f, 0, pi)
    &rArr; 2
</pre></div>

<p>You may use <code>feval</code> to call a function using function handle, or
simply write the name of the function handle followed by an argument
list.  If there are no arguments, you must use an empty argument list
&lsquo;<samp>()</samp>&rsquo;.  For example:
</p>
<div class="example">
<pre class="example">f = @sin;
feval (f, pi/4)
    &rArr; 0.70711
f (pi/4)
    &rArr; 0.70711
</pre></div>

<a name="XREFis_005ffunction_005fhandle"></a><dl>
<dt><a name="index-is_005ffunction_005fhandle"></a><em></em> <strong>is_function_handle</strong> <em>(<var>x</var>)</em></dt>
<dd><p>Return true if <var>x</var> is a function handle.
</p>
<p><strong>See also:</strong> <a href="Built_002din-Data-Types.html#XREFisa">isa</a>, <a href="Data-Types.html#XREFtypeinfo">typeinfo</a>, <a href="Built_002din-Data-Types.html#XREFclass">class</a>, <a href="#XREFfunctions">functions</a>.
</p></dd></dl>


<a name="XREFfunctions"></a><dl>
<dt><a name="index-functions"></a><em><var>s</var> =</em> <strong>functions</strong> <em>(<var>fcn_handle</var>)</em></dt>
<dd><p>Return a structure containing information about the function handle
<var>fcn_handle</var>.
</p>
<p>The structure <var>s</var> always contains these three fields:
</p>
<dl compact="compact">
<dt>function</dt>
<dd><p>The function name.  For an anonymous function (no name) this will be the
actual function definition.
</p>
</dd>
<dt>type</dt>
<dd><p>Type of the function.
</p>
<dl compact="compact">
<dt>anonymous</dt>
<dd><p>The function is anonymous.
</p>
</dd>
<dt>private</dt>
<dd><p>The function is private.
</p>
</dd>
<dt>overloaded</dt>
<dd><p>The function overloads an existing function.
</p>
</dd>
<dt>simple</dt>
<dd><p>The function is a built-in or m-file function.
</p>
</dd>
<dt>subfunction</dt>
<dd><p>The function is a subfunction within an m-file.
</p></dd>
</dl>

</dd>
<dt>file</dt>
<dd><p>The m-file that will be called to perform the function.  This field is empty
for anonymous and built-in functions.
</p></dd>
</dl>

<p>In addition, some function types may return more information in additional
fields.
</p>
<p><strong>Warning:</strong> <code>functions</code> is provided for debugging purposes only.
Its behavior may change in the future and programs should not depend on any
particular output format.
</p>

<p><strong>See also:</strong> <a href="#XREFfunc2str">func2str</a>, <a href="#XREFstr2func">str2func</a>.
</p></dd></dl>


<a name="XREFfunc2str"></a><dl>
<dt><a name="index-func2str"></a><em></em> <strong>func2str</strong> <em>(<var>fcn_handle</var>)</em></dt>
<dd><p>Return a string containing the name of the function referenced by the
function handle <var>fcn_handle</var>.
</p>
<p><strong>See also:</strong> <a href="#XREFstr2func">str2func</a>, <a href="#XREFfunctions">functions</a>.
</p></dd></dl>


<a name="XREFstr2func"></a><dl>
<dt><a name="index-str2func"></a><em></em> <strong>str2func</strong> <em>(<var>fcn_name</var>)</em></dt>
<dd><p>Return a function handle constructed from the string <var>fcn_name</var>.
</p>
<p>Previous versions of Octave accepted an optional second argument,
<code>&quot;global&quot;</code>, that caused str2func to ignore locally visible
functions.  This option is no longer supported.
</p>
<p><strong>See also:</strong> <a href="#XREFfunc2str">func2str</a>, <a href="Inline-Functions.html#XREFinline">inline</a>, <a href="#XREFfunctions">functions</a>.
</p></dd></dl>


<hr>
<div class="header">
<p>
Next: <a href="Anonymous-Functions.html#Anonymous-Functions" accesskey="n" rel="next">Anonymous Functions</a>, Up: <a href="Function-Handles-Anonymous-Functions-Inline-Functions.html#Function-Handles-Anonymous-Functions-Inline-Functions" accesskey="u" rel="up">Function Handles Anonymous Functions Inline Functions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>



</body>
</html>