(PHP 4 >= 4.0.4, PHP 5)
gmp_scan1 — Scan for 1
Scans a, starting with bit start, towards more significant bits, until the first set bit is found.
The number to scan.
可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。
The starting bit.
Returns the index of the found bit, as an integer. If no set bit is found, -1 is returned.
Example #1 gmp_scan1() example 以上例程会输出：
<?php
// "1" bit is found at position 3. index starts at 0
$s1 = gmp_init("01000", 2);
echo gmp_scan1($s1, 0) . "
";
// "1" bit is found at position 9. index starts at 5
$s2 = gmp_init("01000001111", 2);
echo gmp_scan1($s2, 5) . "
";
?>
3
9