-char* convert_from_utf8(convert_t conv, const char* input, int* conv_fails);
-char* convert_to_utf8(convert_t conv, const char* input);
+char* convert_from_utf8(convert_t conv, const char* input, int* conv_fails,
+ size_t* output_len);
+char* convert_to_utf8(convert_t conv, const char* input, size_t input_len);