[mpich-discuss] Error check in MPI_Startall with count=0

When count= 0, mpich should not raise error if array_of_requests is NULL. Otherwise, one has to write code like if (count) MPI_Startall(count, reqs). Note reqs is often NULL if count=0. See also MPI_Waitall, which has the correct logic. MPI_Startall(int count, MPI_Request array_of_requests[]) { ... MPIR_ERRTEST_COUNT(count, mpi_errno); MPIR_ERRTEST_ARGNULL(array_of_requests, "array_of_requests", mpi_errno); } --Junchao Zhang