Scan for 1

# gmp_scan1

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

gmp_scan1 — 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.

  A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init() with automatic base detection (i.e. when `base` is equal to 0).

`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

Example #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";
?>`

The above example will output:

    3
    9

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