mirror of
https://github.com/sigmasternchen/php-doc-en
synced 2025-03-15 16:38:54 +00:00
75 lines
2.2 KiB
XML
75 lines
2.2 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
|
|
<!-- $Revision$ -->
|
|
|
|
<book xml:id="book.bc" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
|
|
<?phpdoc extension-membership="bundled" ?>
|
|
<title>BCMath Arbitrary Precision Mathematics</title>
|
|
<titleabbrev>BC Math</titleabbrev>
|
|
|
|
<!-- {{{ preface -->
|
|
<preface xml:id="intro.bc">
|
|
&reftitle.intro;
|
|
<para>
|
|
For arbitrary precision mathematics PHP offers BCMath which
|
|
supports numbers of any size and precision up to <literal>2147483647</literal> (or <literal>0x7FFFFFFF</literal>) decimal digits,
|
|
if there is sufficient memory, represented as strings.
|
|
</para>
|
|
<para>
|
|
Valid (aka. well-formed) BCMath numbers are strings which match the regular expression
|
|
<literal>/^[+-]?[0-9]*(\.[0-9]*)?$/</literal>.
|
|
</para>
|
|
<caution>
|
|
<para>
|
|
Passing values of type <type>float</type> to a BCMath function which expects
|
|
a <type>string</type> as operand may not have the desired effect due to the
|
|
way PHP converts <type>float</type> values to <type>string</type>, namely
|
|
that the <type>string</type> may be in exponential notation (which is not
|
|
supported by BCMath), and that, prior to PHP 8.0.0, the decimal separator is locale dependent
|
|
(while BCMath always expects a decimal point).
|
|
</para>
|
|
<informalexample>
|
|
<programlisting role="php">
|
|
<![CDATA[
|
|
<?php
|
|
$num1 = 0; // (string) 0 => '0'
|
|
$num2 = -0.000005; // (string) -0.000005 => '-5.05E-6'
|
|
echo bcadd($num1, $num2, 6); // => '0.000000'
|
|
|
|
setlocale(LC_NUMERIC, 'de_DE'); // uses a decimal comma
|
|
$num2 = 1.2; // (string) 1.2 => '1,2'
|
|
echo bcsub($num1, $num2, 1); // => '0.0'
|
|
?>
|
|
]]>
|
|
</programlisting>
|
|
</informalexample>
|
|
</caution>
|
|
</preface>
|
|
<!-- }}} -->
|
|
|
|
&reference.bc.setup;
|
|
&reference.bc.constants;
|
|
&reference.bc.reference;
|
|
|
|
</book>
|
|
|
|
<!-- Keep this comment at the end of the file
|
|
Local variables:
|
|
mode: sgml
|
|
sgml-omittag:t
|
|
sgml-shorttag:t
|
|
sgml-minimize-attributes:nil
|
|
sgml-always-quote-attributes:t
|
|
sgml-indent-step:1
|
|
sgml-indent-data:t
|
|
indent-tabs-mode:nil
|
|
sgml-parent-document:nil
|
|
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
|
|
sgml-exposed-tags:nil
|
|
sgml-local-catalogs:nil
|
|
sgml-local-ecat-files:nil
|
|
End:
|
|
vim600: syn=xml fen fdm=syntax fdl=2 si
|
|
vim: et tw=78 syn=sgml
|
|
vi: ts=1 sw=1
|
|
-->
|
|
|