rem: icalerrno = ICAL_MALFORMEDDATA_ERROR;
add: icalerror_set_errno(ICAL_MALFORMEDDATA_ERROR);
context: char* icalvalue_attach_as_ical_string(icalvalue* value) {    struct icalattachtype a;    char * str;    icalerror_check_arg_rz( (value!=0),"value");    a = icalvalue_get_attach(value);    if (a.binary != 0) {	return  icalvalue_binary_as_ical_string(value);    } else if (a.base64 != 0) {	str = (char*)icalmemory_tmp_buffer(strlen(a.base64)+1);	strcpy(str,a.base64);	return str;    } else if (a.url != 0){	return icalvalue_string_as_ical_string(value);    } else {	icalerrno = ICAL_MALFORMEDDATA_ERROR;	return 0;    }}