diff --git a/src/df.c b/src/df.c
index 41bda87..f4844e7 100644
--- a/src/df.c
+++ b/src/df.c
@@ -798,16 +798,22 @@ main (int argc, char **argv)
   posix_format = false;
   exit_status = EXIT_SUCCESS;
 
-  while ((c = getopt_long (argc, argv, "aB:iF:hHklmPTt:vx:", long_options, NULL))
-	 != -1)
+  while (true)
     {
+      int oi = -1;
+      int c = getopt_long (argc, argv, "aB:iF:hHklmPTt:vx:", long_options, &oi);
+      if (c == -1)
+	break;
+
       switch (c)
 	{
 	case 'a':
 	  show_all_fs = true;
 	  break;
 	case 'B':
-	  human_output_opts = human_options (optarg, true, &output_block_size);
+	  human_output_opts =
+	    human_options (optarg, true, OPT_STR (oi, c, long_options),
+			   &output_block_size);
 	  break;
 	case 'i':
 	  inode_format = true;
@@ -874,7 +880,7 @@ main (int argc, char **argv)
 	}
       else
 	human_output_opts = human_options (getenv ("DF_BLOCK_SIZE"), false,
-					   &output_block_size);
+					   NULL, &output_block_size);
     }
 
   /* Fail if the same file system type was both selected and excluded.  */
diff --git a/src/du.c b/src/du.c
index 57678d9..cbfbbb5 100644
--- a/src/du.c
+++ b/src/du.c
@@ -697,12 +697,17 @@ main (int argc, char **argv)
 
   exclude = new_exclude ();
 
-  human_output_opts = human_options (getenv ("DU_BLOCK_SIZE"), false,
+  human_output_opts = human_options (getenv ("DU_BLOCK_SIZE"), false, NULL,
 				     &output_block_size);
 
-  while ((c = getopt_long (argc, argv, DEBUG_OPT "0abchHklmsxB:DLPSX:",
-			   long_options, NULL)) != -1)
+  while (true)
     {
+      int oi = -1;
+      int c = getopt_long (argc, argv, DEBUG_OPT "0abchHklmsxB:DLPSX:",
+			   long_options, &oi);
+      if (c == -1)
+	break;
+
       switch (c)
 	{
 #if DU_DEBUG
@@ -793,7 +798,9 @@ main (int argc, char **argv)
 	  break;
 
 	case 'B':
-	  human_output_opts = human_options (optarg, true, &output_block_size);
+	  human_output_opts =
+	    human_options (optarg, true, OPT_STR (oi, c, long_options),
+			   &output_block_size);
 	  break;
 
 	case 'D': /* This will eventually be 'H' (-H), too.  */
diff --git a/src/ls.c b/src/ls.c
index ee73622..c29b62a 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -1450,7 +1450,7 @@ decode_switches (int argc, char **argv)
 
   {
     char const *ls_block_size = getenv ("LS_BLOCK_SIZE");
-    human_output_opts = human_options (ls_block_size, false,
+    human_output_opts = human_options (ls_block_size, false, NULL,
 				       &output_block_size);
     if (ls_block_size || getenv ("BLOCK_SIZE"))
       file_output_block_size = output_block_size;
@@ -1506,10 +1506,15 @@ decode_switches (int argc, char **argv)
       }
   }
 
-  while ((c = getopt_long (argc, argv,
-			   "abcdfghiklmnopqrstuvw:xABCDFGHI:LNQRST:UXZ1",
-			   long_options, NULL)) != -1)
+  while (true)
     {
+      int oi = -1;
+      int c = getopt_long (argc, argv,
+			   "abcdfghiklmnopqrstuvw:xABCDFGHI:LNQRST:UXZ1",
+			   long_options, &oi);
+      if (c == -1)
+	break;
+
       switch (c)
 	{
 	case 'a':
@@ -1793,7 +1798,9 @@ decode_switches (int argc, char **argv)
 	  break;
 
 	case BLOCK_SIZE_OPTION:
-	  human_output_opts = human_options (optarg, true, &output_block_size);
+	  human_output_opts =
+	    human_options (optarg, true, OPT_STR (oi, c, long_options),
+			   &output_block_size);
 	  file_output_block_size = output_block_size;
 	  break;