GMP
PHP Manual

gmp_setbit

(PHP 4 >= 4.0.4, PHP 5)

gmp_setbit — Set bit

说明

void gmp_setbit ( resource &$a , int $index [, bool $set_clear ] )

Sets bit index in a .

参数

a

The number being set to.

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

The set bit.

set_clear

Defines if the bit is set to 0 or 1. By default the bit is set to 1. Index starts at 0.

返回值

A GMP number resource.

范例

Example#1 gmp_setbit() example

<?php
$a 
gmp_init("0xfd");
gmp_setbit($a1); // index starts at 0
echo gmp_strval($a) . "\n";
?>

上例将输出:

255

注释

Note: Unlike most of the other GMP functions, gmp_setbit() 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