(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
gmp_scan1 — Scan for 1
Scans num1, starting with bit
start, towards more significant bits,
until the first set bit is found.
Returns the index of the found bit, as an int. If no set bit is found, -1 is returned.
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";
?>
以上例程会输出：
3 9