convert_to_string without an E_NOTICE

Hello, I have a few questions about error reporting in extensions for 5.3.1. I need to convert any IS_OBJECT zval to char* without issuing an error; failed conversions must throw. I've tried this inside a PHP_METHOD: zend_error_handling error_handling; zend_replace_error_handling(EH_THROW, NULL, &error_handling TSRMLS_CC); switch (Z_TYPE_P(arg)) { case IS_OBJECT: { zval tmp(*arg); zval_copy_ctor(&tmp); convert_to_string(&tmp); ... } .. } That has the desired effect of throwing an instance of Exception (Object of class Whatever could not be converted to string), but for some reason also causes an E_NOTICE (same message), with a wrong line number. The number is 0 in 5.3.1 and numberoflines + 1 in 5.2.11 with php_set_error_handling(EH_THROW, zend_exception_get_default(TSRMLS_C) TSRMLS_CC); the one reported by the exception is correct (I'm mentioning this in hope that maybe it can help diagnose my problem). I need to get rid of the E_NOTICE. What should I do instead of or in addition to the convert_to_string? I don't want to duplicate the standard error message, and I'd like to leave the details of what exactly is an object convertible to string and how is that conversion performed to the ZE. -- Roman Neuhauser