... Adds an unset element. add_assoc_bool(zval *array, char *key, int b);() . ... Adding an element to an associative array. zval *new_array, *new_element; char *key = "element_key"; MAKE_STD_ZVAL(new_array); MAKE_STD_ZVAL(new_element); if(array_init(new_array) == FAILURE) { // do error handling here } ZVAL_LONG(new_element, 10); if(zend_hash_update(new_array->value.ht, key, strlen(key) + 1, (void *)&new_element, sizeof(zval *), NULL) == FAILURE) { // do error handling here } . ...