Function mpi::ffi::PMPI_Comm_create_keyval

pub unsafe extern fn PMPI_Comm_create_keyval(comm_copy_attr_fn: MPI_Comm_copy_attr_function,
                                             comm_delete_attr_fn: MPI_Comm_delete_attr_function,
                                             comm_keyval: *mut c_int,
                                             extra_state: *mut c_void)
                                             -> c_int