is_bool — Tests whether a value is a boolean.
mixed value: Value or
variable to test
TRUE if the value is a boolean; FALSE otherwise
is_bool() checks whether value is a boolean. If so, the function
returns TRUE. If not, FALSE is
PHP Version: 3+, 4+
Example 1390. Check whether
a value is a boolean
$value = NULL;
or die ('<b>Exiting Program:</b> Variable $value is not a boolean!');
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing
(Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch).
This material may be distributed only subject to the terms and conditions set forth
in the Open Publication License, v1.0 or later (the latest version is presently available at
The authors of this book have elected not to choose any options under the OPL. This online book was obtained
and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4
for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All
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