PHP | gmp_neg() Function (original) (raw)

Last Updated : 11 Jul, 2025

The gmp_neg() function is an in-built function in PHP which returns the negative of a GMP number (GNU Multiple Precision).Syntax :

gmp_neg( $num )

Parameters : The function accepts only one mandatory parameter $num which can be either a GMP number resource in PHP 5.5 or a GMP object in PHP version 5.6 and later, or numeric strings can be passed to the function provided that it is possible to convert those strings to numbers.Return Values : This function returns a GMP number (in PHP 5.5 and earlier) or a GMP object (in PHP 5.6 and later) which is negative of the value of $num.Examples :

Input : $num = 255 Output : -255

Input : $num = 128 Output : -128

Below programs will illustrate the gmp_neg() function :Program 1:

php `

`

Output:

-255

Program 2:

php `

`

Output:

-314567128

Reference : https://www.php.net/manual/en/function.gmp-neg.php