is_nan() - math

Checks whether val is 'not a number', 
   like the result of acos(1.01).

Parameters : 
 val - The value to check 

Syntax

bool is_nan
    ( float $val
   )

Example

<?php// Invalid calculation, will return a // NaN value$nan = acos(8);var_dump($nan, is_nan($nan));?>

Output / Return Value

Limitations

Alternatives / See Also

Reference