gmp_scan1

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

gmp_scan1 — Scan for 1

说明

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.

参数

num1

The number to scan.

GMP 对象或 int ，或数字string。

start

The starting bit.

返回值

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

范例

示例 #1 gmp_scan1() example


<?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";
?>

以上例程会输出：

3
9