PHP: gmp_cmp - Manual

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

gmp_cmp — Compare numbers

Description

Parameters

num1

A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init() with automatic base detection (i.e. when base is equal to 0).

num2

A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init() with automatic base detection (i.e. when base is equal to 0).

Return Values

Returns a positive value if a > b, zero if a = b and a negative value if a < b.

Examples

<?php
$cmp1 = gmp_cmp("1234", "1000"); // greater than
$cmp2 = gmp_cmp("1000", "1234"); // less than
$cmp3 = gmp_cmp("1234", "1234"); // equal to

echo "$cmp1 $cmp2 $cmp3\n";
?>

I've encountered a memory leak in gmp_cmp if a literal string is used as the second value inside of loops. A workaround is to initialize first, then use the variable. I wasn't able to generate a minimum code sample, it's something more complicated, but I was able to fix it as follows:

<?php

$x = gmp_init(strval(mt_rand()));

// Depending on surrounding code, may have leaks
while (true)
{
    if (!gmp_cmp($x, '1'))
        print 'one'."\n";
}

// Usually doesn't have leaks
$one = gmp_init('1');

while (true)
{
    if (!gmp_cmp($x, $one))
        print 'one'."\n";
}

?>