PHP 5.4.35 Released

gmp_testbit

(PHP 5 >= 5.3.0)

gmp_testbitTests if a bit is set

说明

bool gmp_testbit ( GMP $a , int $index )

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 index is less than zero, and FALSE is returned.

范例

Example #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
7 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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