What is the purpose of the PHP ceil function?

The `ceil()` function is a mathematical function in PHP that rounds a floating-point number or numerical value up to the nearest integer and returns the result.

This means that the `ceil()` function will round the parameter value up to the nearest larger integer than the original value. It will always round up, regardless of whether the original value is positive or negative. If the parameter is already an integer value, it will return the original value itself.

Here is the syntax for the `ceil()` function:

ceil(float $value): float

In this case, `$value` is a number or decimal that needs to be rounded up. The `ceil()` function will return a float as a result, which is the rounded up value.

Here is an example of using the `ceil()` function:

$num1 = 5.4;
$num2 = -9.7;
$result1 = ceil($num1); // 输出：6
$result2 = ceil($num2); // 输出：-9

In the above example, the `ceil()` function rounds $num1 up to 6 and $num2 up to -9.