PHP | gmp_sign() Function (original) (raw)

Last Updated : 11 Jul, 2025

The gmp_sign() is an in-built function in PHP which checks the sign of a given GMP number (GNU Multiple Precision: For large numbers).Syntax:

gmp_sign($num)

Parameters: This function accepts one GMP number $num as mandatory parameter shown in the above syntax. This parameter can be a GMP object in PHP version 5.6 and later, or we are also allowed to pass a numeric string provided that it is possible to convert that string to a number.Return Value: The function checks the sign of the given number $num and returns three values depending on the number as described below:

• Returns 1 - $num is positive
• Returns -1 - $num is negative
• Returns 0 - $num is zero

Examples:

Input : $num=9 Output : 1

Input : $num=-8 Output : -1

Input : $num=0 Output : 0

Below programs illustrate the gmp_sign() function:Program 1: The program below demonstrates the working of gmp_sign() function when GMP number is passed as an argument.

php `

`

Output:

-1 1 0

Program 2: The program below demonstrates the working of gmp_sign() when numeric string is passed as an argument.

php `

`

Output:

-1 1 0

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