# gmp_perfect_square

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

gmp_perfect_square — Perfect square check

### 说明

gmp_perfect_square ( GMP `$a` ) : bool

Check if a number is a perfect square.

### 参数

`a`

  The number being checked as a perfect square.

  可以是一个 GMP 数据 resouce，或一个可以转换为数值的字符串。

### 返回值

Returns `TRUE` if `a` is a perfect square, `FALSE` otherwise.

### 范例

Example #1 gmp_perfect_square() example

    <?php
    // 3 * 3, perfect square
    var_dump(gmp_perfect_square("9"));

    // not a perfect square
    var_dump(gmp_perfect_square("7"));

    // 1234567890 * 1234567890, perfect square
    var_dump(gmp_perfect_square("1524157875019052100"));
    ?>

以上例程会输出：

    bool(true)
    bool(false)
    bool(true)

### 参见

- gmp_perfect_power() - Perfect power check
- gmp_sqrt() - Calculate square root
- gmp_sqrtrem() - Square root with remainder