The is_bool() function is a built-in function in PHP that checks whether a variable is a boolean or not. A boolean is a data type that can have one of two values, either true or false.


The syntax of the is_bool() function is as follows:

bool is_bool(mixed $var)

The function takes a single parameter, $var, which is the variable to be checked for being a boolean. The function returns true if the variable is a boolean, and false otherwise.

Example Usage

Here is an example of how to use the is_bool() function in PHP:

$var1 = true;
$var2 = "hello";
echo is_bool($var1) . "\n";  // output: 1 (true)
echo is_bool($var2) . "\n";  // output: (false)

In this example, we define two variables: $var1 is a boolean with the value of true, and $var2 is a string. We then use the is_bool() function to check whether each variable is a boolean. The output shows that $var1 is a boolean (true), while $var2 is not a boolean (false).


The is_bool() function is a useful tool for checking whether a variable is a boolean in PHP. It can be used to ensure that a variable is of the expected type before performing operations on it, or to handle booleans and non-booleans in a particular way. By using this function, developers can ensure that their code is working with the correct data types and avoid errors that may occur when working with mixed data types.

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