--- a/src/ov-re-mat.cc
+++ b/src/ov-re-mat.cc
@@ -524,7 +524,7 @@
   for (int i = 0; i < rank; i++)
     hdims[i] = d (rank-i-1);
  
-  space_hid = H5Screate_simple (rank, hdims, (hsize_t *)0);
+  space_hid = H5Screate_simple (rank, hdims, 0);
 
   if (space_hid < 0) return false;
 
@@ -562,7 +562,7 @@
 
   double *mtmp = m.fortran_vec ();
   retval = H5Dwrite (data_hid, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL,
-		     H5P_DEFAULT, (void*) mtmp) >= 0;
+		     H5P_DEFAULT, mtmp) >= 0;
 
   H5Dclose (data_hid);
   H5Sclose (space_hid);
@@ -608,14 +608,14 @@
   else
     {
       dv.resize (rank);
-      for (int i = 0, j = rank - 1; i < (int)rank; i++, j--)
+      for (hsize_t i = 0, j = rank - 1; i < rank; i++, j--)
 	dv(j) = hdims[i];
     }
 
   NDArray m (dv);
   double *re = m.fortran_vec ();
   if (H5Dread (data_hid, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, 
-	       H5P_DEFAULT, (void *) re) >= 0) 
+	       H5P_DEFAULT, re) >= 0) 
     {
       retval = true;
       matrix = m;