PHP GMP gmp_cmp() Function

As of my last update in September 2021, PHP’s GMP (GNU Multiple Precision) extension includes the gmp_cmp() function. The gmp_cmp() function is used to compare two GMP numbers and determine their relationship.

Here’s the syntax of the gmp_cmp() function:

int gmp_cmp ( GMP $a , GMP $b )

Parameters:

• $a: The first GMP number for comparison.
• $b: The second GMP number for comparison.

Return value:

• The gmp_cmp() function returns an integer that indicates the relationship between $a and $b. The possible return values are:
• 0: If $a is equal to $b.
• 1: If $a is greater than $b.
• -1: If $a is less than $b.

Example:

$a = gmp_init('123');
$b = gmp_init('456');

$comparisonResult = gmp_cmp($a, $b);

if ($comparisonResult === 0) {
    echo "The GMP numbers are equal.";
} elseif ($comparisonResult === 1) {
    echo "The first GMP number is greater.";
} else {
    echo "The first GMP number is smaller.";
}

In this example, the gmp_cmp() function is used to compare two GMP numbers: 123 and 456. The result is -1, indicating that the first GMP number (123) is smaller than the second GMP number (456).

The gmp_cmp() function is useful for sorting, ordering, and general comparison operations involving large integers. It allows you to compare GMP numbers without converting them to regular PHP integers, which may not handle large integers accurately.

Please note that the GMP extension needs to be enabled in your PHP configuration to use this function. Additionally, the availability of functions may change in newer PHP versions, so always refer to the PHP manual for the specific version you are using.