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gmp_scan1

PHP function Edit on GitHub ✎

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

Scan for 1

Description

gmp_scan1(GMP|int|string $num1, int $start): int

Scans num1, starting with bit start, towards more significant bits, until the first set bit is found.

Parameters

num1

The number to scan.

Parameter

start

The starting bit.

Return Values

Returns the index of the found bit, as an int. If no set bit is found, -1 is returned.

Examples

gmp_scan1() example

php
<?php
// "1" bit is found at position 3. index starts at 0
$s1 = gmp_init("01000", 2);
echo gmp_scan1($s1, 0) . "\n";

// "1" bit is found at position 9. index starts at 5
$s2 = gmp_init("01000001111", 2);
echo gmp_scan1($s2, 5) . "\n";
?>

The above example will output:

output
3
9

Source: reference/gmp/functions/gmp-scan1.xml · from the official PHP manual (php/doc-en)