Fix deprecated use of 0/NULL in gloo/cuda_broadcast_one_to_all.h + 1

Differential Revision: D71284808

Pull Request resolved: #420

Author: r-barnes

gloo/cuda_broadcast_one_to_all.h

@@ -36,13 +36,13 @@ class CudaBroadcastOneToAll : public Algorithm {
   void init(
       typename std::enable_if<
           std::is_same<U, CudaHostWorkspace<T>>::value,
-          typename U::Pointer>::type* = NULL);
+          typename U::Pointer>::type* = nullptr);
 
   template <typename U = W>
   void init(
       typename std::enable_if<
           std::is_same<U, CudaDeviceWorkspace<T>>::value,
-          typename U::Pointer>::type* = NULL);
+          typename U::Pointer>::type* = nullptr);
 
   std::vector<CudaDevicePointer<T>> devicePtrs_;
   std::vector<CudaStream> streams_;