Input Filters - Bugs? - PHP4 Port

Hi, am I correct in assuming that input_filters are allowed todo whatever they want with the value? I am asking, because this is not properly documented and atleast the mbstring extension violates this. First of all it feeds input_filter a value pointer that is NOT allocated with emalloc and secondly it free()s the wrong address in case the input_filter has erealloc()ated value (but most probably the erealloc() will already crash because the memory is allocated with malloc() instead of emalloc()) And the second question is: Is there any argument against backporting the input_filter functionality to PHP4? I do not know what the plans are, but I doubt PHP4 will die out with the release of PHP5 and so the question is if we partly backport new functionality for PHP4 from PHP5 into PHP 4.4 Stefan