Is this the only way to check if an object is an instance of a class, in my case of the DateTime class?
$cls = ReflectionClass("DateTime");
if (! $cls->isInstance( (object) $var ) ) {
// is not an instance
}
It seems a bit heavy to me.
You could try instanceof
Docs...
if ($var instanceof DateTime) {
// true
}
See also is_a
Docs:
if (is_a($var, 'DateTime')) {
// true
}