Is the is_array function reliable?

Question

PHP

Is php is_array function safe?
that is, is there a guarantee that if NOT an array arrives, it will return FALSE for any?

Answer 1

On the example of PHP5.6.14
ext/standard/type.c PHP_FUNCTION(is_array) calls php_is_type (the function is defined in the same place, just above)
It checks for equality Z_TYPE_PP(arg).
Z_TYPE_PP, respectively, macro from Zend/zend_operators.h

#define Z_TYPE(zval)		(zval).type
#define Z_TYPE_P(zval_p)	Z_TYPE(*zval_p)
#define Z_TYPE_PP(zval_pp)	Z_TYPE(**zval_pp)

As you can see, direct access to the type field of the zval structure base for zend. Well, it cannot lie, either IS_ARRAY and is_array will give true or something else and the result will be false.