MPI_Comm_get_info(3) on Linux
The text efce75788d24, as Debian 9 (Stretch) shipped it.
Returns a new info object containing the hints of the communicator associated with comm. The current setting of all hints actually used by the system related to this communicator is returned in info_used. If no such hints exist, a handle to a newly created info object is returned that contains no key/value pair. The user is responsible for freeing info_used via MPI_INFO_FREE.