(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_pow — Raise number into power
baseThe base number.
PHP 5.5 之前为 GMP 数值资源，PHP 5.6 之后为 GMP 对象或数字，或可以转为数字的字符串。
exp
The positive power to raise the base.
The new (raised) number, as a GMP number. The case of
0^0 yields 1.
Example #1 gmp_pow() example
<?php
$pow1 = gmp_pow("2", 31);
echo gmp_strval($pow1) . "\n";
$pow2 = gmp_pow("0", 0);
echo gmp_strval($pow2) . "\n";
$pow3 = gmp_pow("2", -1); // Negative exp, generates warning
echo gmp_strval($pow3) . "\n";
?>
以上例程会输出：
2147483648 1