Log

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Returns the logarithm base $base of $arg

namespace HH\Lib\Math;

function log(
  num $arg,
  ?num $base = NULL,
): float;

For the exponential function, see Math\exp().

Parameters

• num $arg
• ?num $base = NULL

Returns

• float

Examples

$x = 10;
$log = Math\log($x);
echo "Log is $log \n"; // Output: Log is 2.302585092994