gmp_testbit
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
gmp_testbit — Tests if a bit is set
参数
num-
GMP 对象、int 或 string，可以按照跟在 gmp_init() 中使用字符串并自动检测 base（即当 base 等于 0 时）相同的逻辑将其解释为数字。
index-
The bit to test
示例
示例 #1 gmp_testbit() example
<?php
$n = gmp_init("1000000");
var_dump(gmp_testbit($n, 1));
gmp_setbit($n, 1);
var_dump(gmp_testbit($n, 1));
?>以上示例会输出：
bool(false) bool(true)
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用户贡献的备注 1 note
bluej100@gmail ¶
17 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.