Function mpi::ffi::PMPI_Grequest_start

pub unsafe extern fn PMPI_Grequest_start(query_fn: MPI_Grequest_query_function,
                                         free_fn: MPI_Grequest_free_function,
                                         cancel_fn: MPI_Grequest_cancel_function,
                                         extra_state: *mut c_void,
                                         request: *mut MPI_Request)
                                         -> c_int