(PHP 4 >= 4.0.4, PHP 5)
gmp_neg — Negate number
Returns the negative value of a number.
It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.
Returns -a , as a GMP number.
Example #1 gmp_neg() example
<?php
$neg1 = gmp_neg("1");
echo gmp_strval($neg1) . "\n";
$neg2 = gmp_neg("-1");
echo gmp_strval($neg2) . "\n";
?>
上例将输出：
-1 1