is_bool()

is_bool() — Finds out whether a variable is a boolean.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

Signature

is_bool(mixed $value): bool

Parameters

Return value

Returns true if value is a bool, false otherwise.

Example

A runnable snippet:

$a = false; $b = 0; // Since $a is a boolean, it will return true if (is_bool($a) === true) { echo "Yes, this is a boolean\n"; } // Since $b is not a boolean, it will return false if (is_bool($b) === false) { echo "No, this is not a boolean\n"; }

See also

is_float(), is_int(), is_string(), is_object(), is_array()

All PHP 8.5 built-in functions

Reference card built from the PHP manual page is_bool() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.