Iso C binding and C uint8_t type

[Angelo Graziosi]

Which iso C binding constant can we use to interface a C routine using the C type uint8_t? For example

  void print_uint8_t(uint8_t u)
  {
      ...
  }

C_INT, C_INT8_T, C_INT16_T, C_CHAR or what else?

TIA,
 Angelo.