(PHP 4 >= 4.0.4, PHP 5, PHP 7)
gmp_random — Random number
本函数已自 PHP 7.2.0 起被废弃，并自 PHP 8.0.0 起被移除。 强烈建议不要依赖本函数。
Generate a random number. The number will be between 0 and (2 ** n) - 1,
where n is the number of bits per limb multiplied by limiter.
If limiter is negative, negative numbers are generated.
A limb is an internal GMP mechanism. The number of bits in a limb is not static, and can vary from system to system. Generally, the number of bits in a limb is either 32 or 64, but this is not guaranteed.
本函数并不会生成安全加密的值，并且不可用于加密或者要求返回值不可猜测的目的。
如果需要加密安全随机，则可以将 Random\Engine\Secure 引擎用于 Random\Randomizer。对于简单的用例，random_int() 和 random_bytes() 函数提供了操作系统的 CSPRNG 支持的方便且安全的 API。
A random GMP number.
示例 #1 gmp_random() example
<?php
$rand1 = gmp_random(1); // random number from 0 to 1 * bits per limb
$rand2 = gmp_random(2); // random number from 0 to 2 * bits per limb
echo gmp_strval($rand1) . "\n";
echo gmp_strval($rand2) . "\n";
?>以上示例会输出：
1915834968 8642564075890328087