GMP
PHP Manual

gmp_clrbit

(PHP 4 >= 4.0.4, PHP 5)

gmp_clrbit — Clear bit

说明

void gmp_clrbit ( resource &$a , int $index )

Clears (sets to 0) bit index in a . The index starts at 0.

参数

a

It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.

index

It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.

返回值

A GMP number resource.

范例

Example#1 gmp_clrbit() example

<?php
$a = gmp_init("0xff");
gmp_clrbit($a, 0); // index starts at 0, least significant bit
echo gmp_strval($a) . "\n";
?>

上例将输出：

254

注释

Note: Unlike most of the other GMP functions, gmp_clrbit() must be called with a GMP resource that already exists (using gmp_init() for example). One will not be automatically created.

参见

GMP
PHP Manual