message: random.h: minor interface tweaks
diff: @@ -50,8 +50,8 @@ template <typename T> struct PCG32 {
  using UInt64Mask = mask_t<UInt64>;
  /// Initialize the pseudorandom number generator with the \ref seed() function
  - PCG32(UInt64 initstate = PCG32_DEFAULT_STATE,
  - UInt64 initseq = index_sequence<UInt64>() + PCG32_DEFAULT_STREAM) {
  + PCG32(const UInt64 &initstate = PCG32_DEFAULT_STATE,
  + const UInt64 &initseq = index_sequence<UInt64>() + PCG32_DEFAULT_STREAM) {
  seed(initstate, initseq);
  }
  @@ -61,7 +61,7 @@ template <typename T> struct PCG32 {
  * Specified in two parts: a state initializer and a sequence selection
  * constant (a.k.a. stream id)
  */
  - void seed(UInt64 initstate, UInt64 initseq) {
  + void seed(const UInt64 &initstate, const UInt64 &initseq) {
  state = zero<UInt64>();
  inc = sli<1>(initseq) | 1u;
  next_uint32();
  