(PHP 4, PHP 5, PHP 7)
bcmod — Get modulus of an arbitrary precision number
$dividend
   , string $divisor
   [, int $scale = 0
  ] ) : string
   Get the remainder of dividing dividend by
   divisor.
   Unless divisor is zero, the result has the same sign
   as dividend.
  
dividendThe dividend, as a string.
divisorThe divisor, as a string.
   Returns the modulus as a string, or NULL if 
   divisor is 0.
  
| Version | Description | 
|---|---|
| 7.2.0 | dividendanddivisorare no
       longer truncated to integer, so now the behavior of
       bcmod() follows fmod() rather than
       the % operator. | 
| 7.2.0 | The scaleparameter was added. | 
Example #1 bcmod() example
<?php
bcscale(0);
echo bcmod( '5',  '3'); //  2
echo bcmod( '5', '-3'); //  2
echo bcmod('-5',  '3'); // -2
echo bcmod('-5', '-3'); // -2
?>
Example #2 bcmod() with decimals
<?php
bcscale(1);
echo bcmod('5.7', '1.3'); // 0.5 as of PHP 7.2.0; 0 previously
?>