reference/math/functions/is-finite.xml
445fda70c6876c3e903f5ba302248e50fd43cdf6
...
...
@@ -1,44 +1,84 @@
1
1
<?xml version="1.0" encoding="utf-8"?>
2
2
<!-- $Revision$ -->
3
-
<refentry xml:id='function.is-finite' xmlns="http://docbook.org/ns/docbook">
3
+
<refentry xml:id="function.is-finite" xmlns="http://docbook.org/ns/docbook">
4
4
<refnamediv>
5
5
<refname>is_finite</refname>
6
-
<refpurpose>Finds whether a value is a legal finite number</refpurpose>
6
+
<refpurpose>Checks whether a float is finite</refpurpose>
7
7
</refnamediv>
8
+

8
9
<refsect1 role="description">
9
10
&reftitle.description;
10
-
<methodsynopsis>
11
-
<type>bool</type><methodname>is_finite</methodname>
12
-
<methodparam><type>float</type><parameter>val</parameter></methodparam>
13
-
</methodsynopsis>
11
+
<methodsynopsis>
12
+
<type>bool</type><methodname>is_finite</methodname>
13
+
<methodparam><type>float</type><parameter>num</parameter></methodparam>
14
+
</methodsynopsis>
15
+
<para>
16
+
Returns whether the given <parameter>num</parameter> is a finite float.
17
+
</para>
14
18
<para>
15
-
Checks whether <parameter>val</parameter> is a legal finite
16
-
on this platform.
19
+
A finite float is neither <literal>NAN</literal> (<function>is_nan</function>),
20
+
nor infinite (<function>is_infinite</function>).
17
21
</para>
18
22
</refsect1>
23
+

19
24
<refsect1 role="parameters">
20
25
&reftitle.parameters;
21
26
<para>
22
27
<variablelist>
23
28
<varlistentry>
24
-
<term><parameter>val</parameter></term>
29
+
<term><parameter>num</parameter></term>
25
30
<listitem>
26
31
<para>
27
-
The value to check
32
+
The &float; to check
28
33
</para>
29
34
</listitem>
30
35
</varlistentry>
31
36
</variablelist>
32
37
</para>
33
38
</refsect1>
39
+

34
40
<refsect1 role="returnvalues">
35
41
&reftitle.returnvalues;
36
42
<para>
37
-
&true; if <parameter>val</parameter> is a legal finite
38
-
number within the allowed range for a PHP float on this platform,
39
-
else &false;.
43
+
&true; if <parameter>num</parameter> is none of <literal>NAN</literal>,
44
+
<literal>INF</literal>, <literal>-INF</literal>, else &false;.
40
45
</para>
41
46
</refsect1>
47
+

48
+
<refsect1 role="examples">
49
+
&reftitle.examples;
50
+
<para>
51
+
<example>
52
+
<title><function>is_finite</function> example</title>
53
+
<programlisting role="php">
54
+
<![CDATA[
55
+
<?php
56
+
$float = 1.2345;
57
+
var_dump($float, is_finite($float));
58
+

59
+
$nan = sqrt(-1);
60
+
var_dump($nan, is_finite($nan));
61
+

62
+
$inf = 1e308 * 2;
63
+
var_dump($inf, is_finite($inf));
64
+
?>
65
+
]]>
66
+
</programlisting>
67
+
&example.outputs;
68
+
<screen>
69
+
<![CDATA[
70
+
float(1.2345)
71
+
bool(true)
72
+
float(NAN)
73
+
bool(false)
74
+
float(INF)
75
+
bool(false)
76
+
]]>
77
+
</screen>
78
+
</example>
79
+
</para>
80
+
</refsect1>
81
+

42
82
<refsect1 role="seealso">
43
83
&reftitle.seealso;
44
84
<para>
...
...
@@ -49,7 +89,6 @@
49
89
</para>
50
90
</refsect1>
51
91
</refentry>
52
-

53
92
<!-- Keep this comment at the end of the file
54
93
Local variables:
55
94
mode: sgml
56
95