int conversion_set_unknown(convert_t conv, const char* unknown);
int conversion_set_output_buffer(convert_t conv, conv_buffer_t buf);
void cleanup_utf8_conversion(convert_t conv);
-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);
char* convert_to_utf8_incremental(convert_t conv,
const char* input, size_t input_len);