gmp_testbit()

(PHP 5 >= 5.3.0, PHP 7)

Tests if a bit is set

说明

gmp_testbit(GMP$a,int $index): bool

Tests if the specified bit is set.

参数

$a

可以是一个 GMP数据resouce，或一个可以转换为数值的字符串。

$index

The bit to test

返回值

Returns TRUE if the bit is set in resource$a, otherwise FALSE.

错误／异常

An E_WARNING level error is issued when$indexis less than zero, and FALSE is returned.

范例

gmp_testbit() example

<?php
$n = gmp_init("1000000");
var_dump(gmp_testbit($n, 1));
gmp_setbit($n, 1);
var_dump(gmp_testbit($n, 1));
?>

以上例程会输出：

bool(false)
bool(true)

参见

• gmp_setbit()Set bit
• gmp_clrbit()Clear bit

gmp_testbit will be very useful for my (over 64-bit) bitmask checking.
In the meantime, I think these are the best replacements.
Mostly full:
<?php
(gmp_scan1($a, $index) == $index)
?>
Mostly empty:
<?php
(gmp_scan0($a, $index) != $index)
?>
Still worst-case O(N), though.