However, it 's perfectly legal to mix ZEND_FE and ZEND_FUNCTION with PHP_FE and PHP_FUNCTION when staying with the same macro set for each function to be declared.
Note: You can't use ZEND_FE in conjunction with PHP_FUNCTION, or PHP_FE in conjunction with ZEND_FUNCTION. However, it's perfectly legal to mix ZEND_FE and ZEND_FUNCTION with PHP_FE and PHP_FUNCTION when staying with the same macro set for each function to be declared. But mixing is not recommended; instead, you're advised to use the ZEND_* macros only.