php man page for gmp_gcd

GMP_GCD(3)								 1								GMP_GCD(3)

gmp_gcd - Calculate GCD

SYNOPSIS
       GMP gmp_gcd (GMP  $a, GMP  $b)

DESCRIPTION
	Calculate greatest common divisor of $a and $b. The result is always positive even if either of, or both, input operands are negative.

PARAMETERS
	      o $a
		-Either  a  GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that it is
		possible to convert the latter to a number.

	      o $b
		-Either a GMP number resource in PHP 5.5 and earlier, a GMP object in PHP 5.6 and later, or a numeric string provided that  it	is
		possible to convert the latter to a number.

RETURN VALUES
	A positive GMP number that divides into both $a and $b.

EXAMPLES
       Example #1

	      gmp_gcd(3) example

	      <?php
	      $gcd = gmp_gcd("12", "21");
	      echo gmp_strval($gcd) . "
";
	      ?>

	      The above example will output:

	      3

PHP Documentation Group 														GMP_GCD(3)