gmp_testbit

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

gmp_testbit — Tests if a bit is set

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

Tests if the specified bit is set.

num: A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init() with automatic base detection (i.e. when base is equal to 0).
index: The bit to test

Returns true if the bit is set in num, otherwise false.

An E_WARNING level error is issued when index is less than zero, and false is returned.

Example #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));
?>

The above example will output:

bool(false)
bool(true)