gmp_setbit

(PHP 4 >= 4.0.4, PHP 5)

gmp_setbit — Set bit

Description

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

Sets bit index in a.

Parameters

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.

Return Values

A GMP number resource.

Examples

Example #1 gmp_setbit() example


<?php
$a = gmp_init("0xfd");
gmp_setbit($a, 1); // index starts at 0
echo gmp_strval($a) . "\n";
?>

The above example will output:

Notes

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.


The third parameter is somewhat confusingly named; it would probably be better described as "$set_state". If true, it sets the bit to 1. If false, it sets the bit to 0. Default is true.



<?php

$num = gmp_init(1);

gmp_setbit($num, 1);

echo 'gmp_setbit(1, 1): '.gmp_strval($num, 2)."\n"; // 11



$num = gmp_init(1);

gmp_setbit($num, 1, true);

echo 'gmp_setbit(1, 1, true): '.gmp_strval($num, 2)."\n"; // 11



$num = gmp_init(1);

gmp_setbit($num, 0, false);

echo 'gmp_setbit(1, 0, false): '.gmp_strval($num, 2)."\n"; // 0

?>

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