gmp_testbit

(PHP 5 >= 5.3.0, PHP 7)

gmp_testbitTests if a bit is set

说明

gmp_testbit ( GMP|int|string $num , int $index ) : bool

Tests if the specified bit is set.

参数

num

GMP 对象或 int ,或数字string

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 index is less than zero, and false is returned.

范例

示例 #1 gmp_testbit() example

<?php
$n 
gmp_init("1000000");
var_dump(gmp_testbit($n1));
gmp_setbit($n1);
var_dump(gmp_testbit($n1));
?>

以上例程会输出:

bool(false)
bool(true)

参见

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User Contributed Notes 1 note

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bluej100@gmail
13 years ago
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.
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