gmp_scan1
PHP function
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(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
num1The number to scan.
Parameter
startThe starting bit.
Return Values
Returns the index of the found bit, as an int. If no set bit is found, -1 is returned.
Errors/Exceptions
Throws a ValueError if start is negative or, as of PHP 8.5.0, too large.
Prior to PHP 8.0.0, an E_WARNING was raised instead.
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