Fix unmatched_returns warnings in STDLIB and Kernel

23 files changed, 166 insertions, 131 deletions

diff --git a/lib/stdlib/src/beam_lib.erl b/lib/stdlib/src/beam_lib.erl
index fe7e0f8e60..7a93fa0f45 100644
--- a/lib/stdlib/src/beam_lib.erl
+++ b/lib/stdlib/src/beam_lib.erl
@@ -904,7 +904,7 @@ call_crypto_server(Req) ->
     end.
 
 call_crypto_server_1(Req) ->
-    gen_server:start({local,?CRYPTO_KEY_SERVER}, ?MODULE, [], []),
+    {ok, _} = gen_server:start({local,?CRYPTO_KEY_SERVER}, ?MODULE, [], []),
     erlang:yield(),
     call_crypto_server(Req).
 
diff --git a/lib/stdlib/src/c.erl b/lib/stdlib/src/c.erl
index 91d317489c..56d435d5d7 100644
--- a/lib/stdlib/src/c.erl
+++ b/lib/stdlib/src/c.erl
@@ -694,7 +694,7 @@ pwd() ->
       Dir :: file:name().
 
 cd(Dir) ->
-    file:set_cwd(Dir),
+    _ = file:set_cwd(Dir),
     pwd().
 
 %% ls()
diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 50812cc532..d743467e97 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -469,7 +469,7 @@ is_compatible_bchunk_format(Tab, Term) ->
 is_dets_file(FileName) ->
     case catch read_file_header(FileName, read, false) of
 	{ok, Fd, FH} ->
-	    file:close(Fd),
+	    _ = file:close(Fd),
 	    FH#fileheader.cookie =:= ?MAGIC;
 	{error, {tooshort, _}} ->
 	    false;
@@ -1384,7 +1384,8 @@ do_apply_op(Op, From, Head, N) ->
             end,
             if
                 From =/= self() ->
-                    From ! {self(), {error, {dets_bug, Name, Op, Bad}}};
+                    From ! {self(), {error, {dets_bug, Name, Op, Bad}}},
+                    ok;
                 true -> % auto_save | may_grow | {delayed_write, _}
                     ok
             end,
@@ -1634,7 +1635,8 @@ start_auto_save_timer(Head) when Head#head.auto_save =:= infinity ->
     ok;
 start_auto_save_timer(Head) ->
     Millis = Head#head.auto_save,
-    erlang:send_after(Millis, self(), ?DETS_CALL(self(), auto_save)).
+    _Ref = erlang:send_after(Millis, self(), ?DETS_CALL(self(), auto_save)),
+    ok.
 
 %% Version 9: Peek the message queue and try to evaluate several
 %% lookup requests in parallel. Evalute delete_object, delete and
@@ -1683,7 +1685,7 @@ stream_end(Head, Pids0, C, N, Next) ->
 	    %%  replies to delete and insert requests even if the
 	    %%  latter requests were made before the lookup requests,
 	    %%  which can be confusing.)
-	    lookup_replies(Found),
+	    _ = lookup_replies(Found),
 	    stream_end1(Pids0, Next, N, C, Head1, PwriteList);
 	Head1 when is_record(Head1, head) ->
 	    stream_end2(Pids0, Pids0, Next, N, C, Head1, ok);	    
@@ -1733,7 +1735,7 @@ lookup_replies(Q) ->
 lookup_replies(P, O, []) ->
     lookup_reply(P, O);
 lookup_replies(P, O, [{P2,O2} | L]) ->
-    lookup_reply(P, O),
+    _ = lookup_reply(P, O),
     lookup_replies(P2, lists:append(O2), L).
 
 %% If a list of Pid then op was {member, Key}. Inlined.
@@ -1790,12 +1792,15 @@ fclose(Head) ->
     {Head1, Res} = perform_save(Head, false),
     case Head1#head.ram_file of
 	true -> 
-	    ignore;
+            Res;
 	false -> 
             dets_utils:stop_disk_map(),
-	    file:close(Head1#head.fptr)
-    end,
-    Res.
+	    Res2 = file:close(Head1#head.fptr),
+            if
+                Res2 =:= ok -> Res;
+                true -> Res2
+            end
+    end.
 
 %% -> {NewHead, Res}
 perform_save(Head, DoSync) when Head#head.update_mode =:= dirty;
@@ -2002,7 +2007,7 @@ remove_fix(Head, Pid, How) ->
     end.
 
 do_stop(Head) ->
-    unlink_fixing_procs(Head),
+    _NewHead = unlink_fixing_procs(Head),
     fclose(Head).
 
 unlink_fixing_procs(Head) ->
@@ -2010,7 +2015,7 @@ unlink_fixing_procs(Head) ->
 	false ->
 	    Head;
 	{_, Counters} ->
-	    lists:map(fun({Pid, _Counter}) -> unlink(Pid) end, Counters),
+	    lists:foreach(fun({Pid, _Counter}) -> unlink(Pid) end, Counters),
 	    Head#head{fixed = false, 
 		      freelists = dets_utils:get_freelists(Head)}
     end.
@@ -2021,8 +2026,9 @@ check_growth(Head) ->
     NoThings = no_things(Head),
     if
 	NoThings > Head#head.next ->
-	    erlang:send_after(200, self(), 
-			      ?DETS_CALL(self(), may_grow)); % Catch up.
+	    _Ref = erlang:send_after
+                     (200, self(), ?DETS_CALL(self(), may_grow)), % Catch up.
+            ok;
 	true ->
 	    ok
     end.
@@ -2123,7 +2129,7 @@ do_open_file([Fname, Verbose], Parent, Server, Ref) ->
 do_open_file([Tab, OpenArgs, Verb], Parent, Server, Ref) ->
     case catch fopen3(Tab, OpenArgs) of
 	{error, {tooshort, _}} ->
-	    file:delete(OpenArgs#open_args.file),
+	    _ = file:delete(OpenArgs#open_args.file),
 	    do_open_file([Tab, OpenArgs, Verb], Parent, Server, Ref);
 	{error, _Reason} = Error ->
 	    err(Error);
@@ -2671,11 +2677,11 @@ fopen_init_file(Tab, OpenArgs) ->
     case catch Mod:initiate_file(Fd, Tab, Fname, Type, Kp, MinSlots, MaxSlots,
 				 Ram, CacheSz, Auto, true) of
 	{error, Reason} when Ram ->
-	    file:close(Fd),
+	    _ = file:close(Fd),
 	    throw({error, Reason});
 	{error, Reason} ->
-	    file:close(Fd),
-	    file:delete(Fname),
+	    _ = file:close(Fd),
+	    _ = file:delete(Fname),
 	    throw({error, Reason});
 	{ok, Head} ->
 	    start_auto_save_timer(Head),
@@ -2730,8 +2736,8 @@ compact(SourceHead) ->
 	       {ok, H} ->
 		   H;
 	       Error ->
-		   file:close(Fd),
-                   file:delete(Tmp),
+		   _ = file:close(Fd),
+                   _ = file:delete(Tmp),
 		   throw(Error)
 	   end,
 
@@ -2748,12 +2754,12 @@ compact(SourceHead) ->
 	    if 
 		R =:= ok -> ok;
 		true ->
-		    file:delete(Tmp),
+		    _ = file:delete(Tmp),
 		    throw(R)
 	    end;
 	Err ->
-	    file:close(Fd),
-            file:delete(Tmp),
+	    _ = file:close(Fd),
+            _ = file:delete(Tmp),
 	    throw(Err)
     end.
 	    
@@ -2777,7 +2783,7 @@ fsck(Fd, Tab, Fname, FH, MinSlotsArg, MaxSlotsArg, Version) ->
 	    BetterSlotNumbers = {MinSlots, BetterNoSlots, MaxSlots},
             case fsck_try(Fd, Tab, FH, Fname, BetterSlotNumbers, Version) of
                 {try_again, _} ->
-                    file:close(Fd),
+                    _ = file:close(Fd),
                     {error, {cannot_repair, Fname}};
                 Else ->
                     Else
@@ -2818,15 +2824,15 @@ fsck_try(Fd, Tab, FH, Fname, SlotNumbers, Version) ->
                     if 
 			R =:= ok -> ok;
 			true ->
-			    file:delete(Tmp),
+			    _ = file:delete(Tmp),
 			    R
 		    end;
 		TryAgainOrError ->
-                    file:delete(Tmp),
+                    _ = file:delete(Tmp),
                     TryAgainOrError
             end;
 	Error -> 
-	    file:close(Fd),
+	    _ = file:close(Fd),
 	    Error
     end.
 
@@ -2855,13 +2861,13 @@ fsck_try_est(Head, Fd, Fname, SlotNumbers, FH) ->
     Bulk = false,
     case Reply of 
         {ok, NoDups, H1} ->
-            file:close(Fd),
+            _ = file:close(Fd),
             fsck_copy(SizeData, H1, Bulk, NoDups);
         {try_again, _} = Return ->
             close_files(Bulk, SizeData, Head),
             Return;
         Else ->
-            file:close(Fd),
+            _ = file:close(Fd),
             close_files(Bulk, SizeData, Head),
 	    Else
     end.
@@ -2896,14 +2902,20 @@ fsck_copy1([SzData | L], Head, Bulk, NoDups) ->
     {LogSz, Pos, {FileName, Fd}, NoObjects} = SzData,
     Size = if NoObjects =:= 0 -> 0; true -> ?POW(LogSz-1) end,
     ExpectedSize = Size * NoObjects,
-    close_tmp(Fd),
-    case file:position(Out, Pos) of
-	{ok, Pos} -> ok;
-	PError -> dets_utils:file_error(FileName, PError)
+    case close_tmp(Fd) of
+        ok -> ok;
+        Err ->
+	    close_files(Bulk, L, Head),
+	    dets_utils:file_error(FileName, Err)
     end,
-    {ok, Pos} = file:position(Out, Pos),
+    case file:position(Out, Pos) of
+        {ok, Pos} -> ok;
+        Err2 ->
+	    close_files(Bulk, L, Head),
+	    dets_utils:file_error(Head#head.filename, Err2)
+        end,
     CR = file:copy({FileName, [raw,binary]}, Out),
-    file:delete(FileName),
+    _ = file:delete(FileName),
     case CR of 
 	{ok, Copied} when Copied =:= ExpectedSize;
 			  NoObjects =:= 0 -> % the segments
@@ -2937,11 +2949,11 @@ free_n_objects(Head, Addr, Size, N) ->
     free_n_objects(NewHead, NewAddr, Size, N-1).
 
 close_files(false, SizeData, Head) ->
-    file:close(Head#head.fptr),
+    _ = file:close(Head#head.fptr),
     close_files(true, SizeData, Head);
 close_files(true, SizeData, _Head) ->
     Fun = fun({_Size, _Pos, {FileName, Fd}, _No}) ->
-		  close_tmp(Fd),
+		  _ = close_tmp(Fd),
 		  file:delete(FileName);
 	     (_) ->
 		  ok
@@ -3261,7 +3273,7 @@ err(Error) ->
 file_info(FileName) ->
     case catch read_file_header(FileName, read, false) of
 	{ok, Fd, FH} ->
-	    file:close(Fd),
+	    _ = file:close(Fd),
             (FH#fileheader.mod):file_info(FH);
 	Other ->
 	    Other
@@ -3290,7 +3302,7 @@ view(FileName) ->
                         X ->
                             X
                     end
-            after file:close(Fd)
+            after _ = file:close(Fd)
             end;
 	X -> 
 	    X
diff --git a/lib/stdlib/src/dets_server.erl b/lib/stdlib/src/dets_server.erl
index 931112088e..268c201047 100644
--- a/lib/stdlib/src/dets_server.erl
+++ b/lib/stdlib/src/dets_server.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 2001-2009. All Rights Reserved.
+%% Copyright Ericsson AB 2001-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -241,8 +241,8 @@ ensure_started() ->
 init() ->
     set_verbose(verbose_flag()),
     process_flag(trap_exit, true),
-    ets:new(?REGISTRY, [set, named_table]),
-    ets:new(?OWNERS, [set, named_table]),
+    ?REGISTRY = ets:new(?REGISTRY, [set, named_table]),
+    ?OWNERS = ets:new(?OWNERS, [set, named_table]),
     ets:new(?STORE, [duplicate_bag]).
 
 verbose_flag() ->
@@ -338,7 +338,7 @@ handle_close(State, Req, {FromPid,_Tag}=From, Tab) ->
                         [{Tab, _Counter, Pid}] ->
 			    do_unlink(Store, FromPid),
 			    true = ets:match_delete(Store, {FromPid, Tab}),
-			    [true = ets:insert(Store, K) || K <- Keep],
+                            true = ets:insert(Store, Keep),
 			    ets:update_counter(?REGISTRY, Tab, -1),
                             pending_call(Tab, Pid, make_ref(), From, [],
                                          remove_user, State)
diff --git a/lib/stdlib/src/dets_utils.erl b/lib/stdlib/src/dets_utils.erl
index 7bbb34dd15..6c176ad513 100644
--- a/lib/stdlib/src/dets_utils.erl
+++ b/lib/stdlib/src/dets_utils.erl
@@ -230,8 +230,12 @@ write_file(Head, Bin) ->
 	    {ok, Fd} ->
 		R1 = file:write(Fd, Bin),
 		R2 = file:sync(Fd),
-		file:close(Fd),
-		if R1 =:= ok -> R2; true -> R1 end;
+		R3 = file:close(Fd),
+                case {R1, R2, R3} of
+                    {ok, ok, R3} -> R3;
+                    {ok, R2, _} -> R2;
+                    {R1, _, _} -> R1
+                end;
 	    Else ->
 		Else
 	end,
@@ -277,12 +281,7 @@ open(FileSpec, Args) ->
     end.
 
 truncate(Fd, FileName, Pos) ->
-    if
-	Pos =:= cur ->
-	    ok;
-	true ->
-	    position(Fd, FileName, Pos)
-    end,
+    _ = [position(Fd, FileName, Pos) || Pos =/= cur],
     case file:truncate(Fd) of
 	ok    -> 
 	    ok;
@@ -327,10 +326,10 @@ pread_close(Fd, FileName, Pos, Size) ->
 	{error, Error} ->
 	    file_error_close(Fd, FileName, {error, Error});
 	{ok, Bin} when byte_size(Bin) < Size ->
-	    file:close(Fd),
+	    _ = file:close(Fd),
 	    throw({error, {tooshort, FileName}});
 	eof ->
-	    file:close(Fd),
+	    _ = file:close(Fd),
 	    throw({error, {tooshort, FileName}});
 	OK -> OK
     end.
@@ -339,7 +338,7 @@ file_error(FileName, {error, Reason}) ->
     throw({error, {file_error, FileName, Reason}}).
 
 file_error_close(Fd, FileName, {error, Reason}) ->
-    file:close(Fd),
+    _ = file:close(Fd),
     throw({error, {file_error, FileName, Reason}}).
 	    
 debug_mode() ->
@@ -977,7 +976,8 @@ dm([{P,<<Sz:32,X:32>>} | Bs], T) ->
     true = ets:insert(T, {P,{pointer,X,Sz}}),
     if 
         Sz =:= 0 -> 
-            X = 0; 
+            X = 0,
+            true;
         true -> 
             true = ets:insert(T, {{pointer,X}, P})
     end,
diff --git a/lib/stdlib/src/dets_v8.erl b/lib/stdlib/src/dets_v8.erl
index 24d6e06ec8..f188502017 100644
--- a/lib/stdlib/src/dets_v8.erl
+++ b/lib/stdlib/src/dets_v8.erl
@@ -199,10 +199,10 @@
 %% -> ok | throw({NewHead,Error})
 mark_dirty(Head) ->
     Dirty = [{?CLOSED_PROPERLY_POS, <<?NOT_PROPERLY_CLOSED:32>>}],
-    dets_utils:pwrite(Head, Dirty),
-    dets_utils:sync(Head),
-    dets_utils:position(Head, Head#head.freelists_p),
-    dets_utils:truncate(Head, cur).
+    {_NewHead, ok} = dets_utils:pwrite(Head, Dirty),
+    ok = dets_utils:sync(Head),
+    {ok, _Pos} = dets_utils:position(Head, Head#head.freelists_p),
+    ok = dets_utils:truncate(Head, cur).
 
 %% -> {ok, head()} | throw(Error)
 initiate_file(Fd, Tab, Fname, Type, Kp, MinSlots, MaxSlots, 
diff --git a/lib/stdlib/src/dets_v9.erl b/lib/stdlib/src/dets_v9.erl
index 308f81c23b..2af93ec800 100644
--- a/lib/stdlib/src/dets_v9.erl
+++ b/lib/stdlib/src/dets_v9.erl
@@ -284,9 +284,9 @@
 %% -> ok | throw({NewHead,Error})
 mark_dirty(Head) ->
     Dirty = [{?CLOSED_PROPERLY_POS, <<?NOT_PROPERLY_CLOSED:32>>}],
-    dets_utils:pwrite(Head, Dirty),
-    dets_utils:sync(Head),
-    dets_utils:position(Head, Head#head.freelists_p),
+    {_H, ok} = dets_utils:pwrite(Head, Dirty),
+    ok = dets_utils:sync(Head),
+    {ok, _Pos} = dets_utils:position(Head, Head#head.freelists_p),
     dets_utils:truncate(Head, cur).
 
 %% -> {ok, head()} | throw(Error) | throw(badarg)
@@ -1385,13 +1385,13 @@ segment_file(SizeT, Head, FileData, SegEnd) ->
 	case Data of
 	    {InFile,In0} ->
 		{OutFile, Out} = temp_file(Head, SizeT, I),
-		file:close(In0),
+		_ = file:close(In0),
 		{ok, In} = dets_utils:open(InFile, [raw,binary,read]),
 		{ok, 0} = dets_utils:position(In, InFile, bof),
 		seg_file(SegAddr, SegAddr, In, InFile, Out, OutFile, SizeT, 
 			 SegEnd),
-		file:close(In),
-		file:delete(InFile),
+		_ = file:close(In),
+		_ = file:delete(InFile),
 		{OutFile,Out};
 	    Objects ->
 		{LastAddr, B} = seg_file(Objects, SegAddr, SegAddr, SizeT, []),
@@ -1702,7 +1702,7 @@ free_list_to_file(Ftab, H, Pos, Sz, Ws, WsSz) ->
     free_list_to_file(Ftab, H, Pos+1, Sz, NWs, NWsSz).
 
 free_lists_from_file(H, Pos) ->
-    dets_utils:position(H#head.fptr, H#head.filename, Pos),
+    {ok, Pos} = dets_utils:position(H#head.fptr, H#head.filename, Pos),
     FL = dets_utils:empty_free_lists(),
     case catch bin_to_tree([], H, start, FL, -1, []) of
 	{'EXIT', _} ->
diff --git a/lib/stdlib/src/digraph_utils.erl b/lib/stdlib/src/digraph_utils.erl
index 807b5c12a1..0e248df453 100644
--- a/lib/stdlib/src/digraph_utils.erl
+++ b/lib/stdlib/src/digraph_utils.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1999-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1999-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -370,5 +370,5 @@ condense('$end_of_table', _T, _SC, _G, _SCG, _I2C) ->
 condense(I, T, SC, G, SCG, I2C) ->
     [{_,C}] = ets:lookup(I2C, I),
     digraph:add_vertex(SCG, C),
-    [digraph:add_edge(SCG, SC, C) || C =/= SC],
+    _ = [digraph:add_edge(SCG, SC, C) || C =/= SC],
     condense(ets:next(T, I), T, SC, G, SCG, I2C).
diff --git a/lib/stdlib/src/epp.erl b/lib/stdlib/src/epp.erl
index 5bd6a224a2..dd0512be4d 100644
--- a/lib/stdlib/src/epp.erl
+++ b/lib/stdlib/src/epp.erl
@@ -644,7 +644,7 @@ leave_file(From, St) ->
 		    enter_file_reply(From, OldName, CurrLoc, CurrLoc),
                     case OldName2 =:= OldName of
                         true ->
-                            From;
+                            ok;
                         false ->
                             NFrom = wait_request(NextSt),
                             enter_file_reply(NFrom, OldName2, OldLoc,
diff --git a/lib/stdlib/src/erl_tar.erl b/lib/stdlib/src/erl_tar.erl
index 4b654833ed..f49c2a64f4 100644
--- a/lib/stdlib/src/erl_tar.erl
+++ b/lib/stdlib/src/erl_tar.erl
@@ -45,10 +45,7 @@ open(Name, Mode) ->
 open1({binary,Bin}, read, _Raw, Opts) ->
     case file:open(Bin, [ram,binary,read]) of
 	{ok,File} ->
-	    case Opts of
-		[compressed] -> ram_file:uncompress(File);
-		[] -> ok
-	    end,
+            _ = [ram_file:uncompress(File) || Opts =:= [compressed]],
 	    {ok,{read,File}};
 	Error ->
 	    Error
diff --git a/lib/stdlib/src/error_logger_tty_h.erl b/lib/stdlib/src/error_logger_tty_h.erl
index ad5891f191..e92142d154 100644
--- a/lib/stdlib/src/error_logger_tty_h.erl
+++ b/lib/stdlib/src/error_logger_tty_h.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -54,7 +54,7 @@ init([]) ->
 handle_event({_Type, GL, _Msg}, State) when node(GL) =/= node() ->
     {ok, State};
 handle_event(Event, State) ->
-    write_event(tag_event(Event),io),
+    ok = write_event(tag_event(Event),io),
     {ok, State}.
 
 handle_info({'EXIT', User, _Reason}, {User, PrevHandler}) ->
@@ -66,10 +66,10 @@ handle_info({'EXIT', User, _Reason}, {User, PrevHandler}) ->
 	     PrevHandler, go_back}
     end;
 handle_info({emulator, GL, Chars}, State) when node(GL) == node() ->
-    write_event(tag_event({emulator, GL, Chars}),io),
+    ok = write_event(tag_event({emulator, GL, Chars}),io),
     {ok, State};
 handle_info({emulator, noproc, Chars}, State) ->
-    write_event(tag_event({emulator, noproc, Chars}),io),
+    ok = write_event(tag_event({emulator, noproc, Chars}),io),
     {ok, State};
 handle_info(_, State) ->
     {ok, State}.
@@ -99,10 +99,11 @@ set_group_leader() ->
 tag_event(Event) ->    
     {erlang:universaltime(), Event}.
 
+%% IOMOd is always 'io'
 write_events(Events,IOMod) -> write_events1(lists:reverse(Events),IOMod).
 
 write_events1([Event|Es],IOMod) ->
-    write_event(Event,IOMod),
+    ok = write_event(Event,IOMod),
     write_events1(Es,IOMod);
 write_events1([],_IOMod) ->
     ok.
diff --git a/lib/stdlib/src/escript.erl b/lib/stdlib/src/escript.erl
index fea718541d..35f6dff57e 100644
--- a/lib/stdlib/src/escript.erl
+++ b/lib/stdlib/src/escript.erl
@@ -771,9 +771,11 @@ interpret(Forms, HasRecs,  File, Args) ->
     ArgsA = erl_parse:abstract(Args, 0),
     Call = {call,0,{atom,0,main},[ArgsA]},
     try
-        erl_eval:expr(Call,
-                      erl_eval:new_bindings(),
-                      {value,fun(I, J) -> code_handler(I, J, Dict, File) end}),
+        _ = erl_eval:expr(Call,
+                          erl_eval:new_bindings(),
+                          {value,fun(I, J) ->
+                                         code_handler(I, J, Dict, File)
+                                 end}),
         my_halt(0)
     catch
         Class:Reason ->
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index 77c8029f59..87e6502668 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -719,7 +719,7 @@ tab2file(Tab, File) ->
 tab2file(Tab, File, Options) ->
     try
 	{ok, FtOptions} = parse_ft_options(Options),
-	file:delete(File),
+	_ = file:delete(File),
 	case file:read_file_info(File) of
 	    {error, enoent} -> ok;
 	    _ -> throw(eaccess)
@@ -750,14 +750,18 @@ tab2file(Tab, File, Options) ->
 		    {fun(Oldstate,Termlist) ->
 			     {NewState,BinList} = 
 				 md5terms(Oldstate,Termlist),
-			     disk_log:blog_terms(Name,BinList),
-			     NewState
+                             case disk_log:blog_terms(Name,BinList) of
+                                 ok -> NewState;
+                                 {error, Reason2} -> throw(Reason2)
+                             end
 		     end,
 		     erlang:md5_init()};
 		false ->
 		    {fun(_,Termlist) ->
-			     disk_log:log_terms(Name,Termlist),
-			     true
+                             case disk_log:log_terms(Name,Termlist) of
+                                 ok -> true;
+                                 {error, Reason2} -> throw(Reason2)
+                             end
 		     end, 
 		     true}
 	    end,
@@ -792,16 +796,16 @@ tab2file(Tab, File, Options) ->
 	    disk_log:close(Name)
 	catch
 	    throw:TReason ->
-		disk_log:close(Name),
-		file:delete(File),
+		_ = disk_log:close(Name),
+		_ = file:delete(File),
 		throw(TReason);
 	    exit:ExReason ->
-		disk_log:close(Name),
-		file:delete(File),
+		_ = disk_log:close(Name),
+		_ = file:delete(File),
 		exit(ExReason);
 	    error:ErReason ->
-		disk_log:close(Name),
-		file:delete(File),
+		_ = disk_log:close(Name),
+		_ = file:delete(File),
 	        erlang:raise(error,ErReason,erlang:get_stacktrace())
 	end
     catch
@@ -901,7 +905,7 @@ file2tab(File, Opts) ->
 		{repaired, Name, _,_} -> %Uh? cannot happen?
 		    case Verify of
 			true ->
-			    disk_log:close(Name),
+			    _ = disk_log:close(Name),
 			    throw(badfile);
 			false ->
 			    get_header_data(Name,Verify)
@@ -1306,7 +1310,10 @@ tabfile_info(File) when is_list(File) ; is_atom(File) ->
 		Other2 ->
 		    throw(Other2)
 	    end,
-	disk_log:close(Name),
+        case disk_log:close(Name) of
+            ok -> ok;
+            {error, Reason} -> throw(Reason)
+        end,
 	{value, N} = lists:keysearch(name, 1, FullHeader),
 	{value, Type} = lists:keysearch(type, 1, FullHeader),
 	{value, P} = lists:keysearch(protection, 1, FullHeader),
diff --git a/lib/stdlib/src/file_sorter.erl b/lib/stdlib/src/file_sorter.erl
index 2bf88959b7..687d72b4bd 100644
--- a/lib/stdlib/src/file_sorter.erl
+++ b/lib/stdlib/src/file_sorter.erl
@@ -547,7 +547,7 @@ files(_I, L, _LSz, #w{seq = 1, out = Out}=W, []) ->
             NW = close_input(W1),
             outfun(close, NW);
         Out ->
-            write_run(L, W, Out),
+            _ = write_run(L, W, Out),
             ok
     end;
 files(_I, L, _LSz, W, []) ->
@@ -638,7 +638,7 @@ last_merge(R, W) when length(R) =< W#w.no_files ->
             NW = close_input(W2),
             outfun(close, NW);
         Out ->
-            merge_files(R, W, Out),
+            _ = merge_files(R, W, Out),
             ok
     end;
 last_merge(R, W) ->
@@ -1110,10 +1110,12 @@ read_fun2(Fd, Bin, Size, FileName, Owner) ->
     end.
        
 close_read_fun(Fd, _FileName, user) ->
-    file:close(Fd);
+    _ = file:close(Fd),
+    ok;
 close_read_fun(Fd, FileName, fsort) ->
-    file:close(Fd),
-    file:delete(FileName).
+    _ = file:close(Fd),
+    _ = file:delete(FileName),
+    ok.
 
 read_objs(Fd, FileName, I, L, Bin0, Size0, LSz, W) ->
     Max = erlang:max(Size0, ?CHUNKSIZE),
@@ -1481,10 +1483,10 @@ cleanup(W) ->
     F = fun(IFun) when is_function(IFun) -> 
                 IFun(close);
            ({Fd,FileName}) ->
-                file:close(Fd),
-                file:delete(FileName);
+                _ = file:close(Fd),
+                _= file:delete(FileName);
            (FileName) -> 
-                file:delete(FileName)
+                _= file:delete(FileName)
         end,
     lists:foreach(F, W1#w.temp).
 
@@ -1502,8 +1504,12 @@ close_out(_) ->
 close_file(Fd, W) ->
     {Fd, FileName} = lists:keyfind(Fd, 1, W#w.temp),
     ?DEBUG("closing ~tp~n", [FileName]),
-    file:close(Fd),
-    W#w{temp = [FileName | lists:keydelete(Fd, 1, W#w.temp)]}.
+    case file:close(Fd) of
+        ok ->
+            W#w{temp = [FileName | lists:keydelete(Fd, 1, W#w.temp)]};
+        Error ->
+            file_error(FileName, Error, W)
+    end.
 
 %%%
 %%% Format 'term'.
@@ -1536,10 +1542,10 @@ file_rterms2(Fd, L, LSz, FileName, Files) when LSz < ?CHUNKSIZE ->
             B = term_to_binary(Term),
             file_rterms2(Fd, [B | L], LSz + byte_size(B), FileName, Files);
         eof ->
-            file:close(Fd),
+            _ = file:close(Fd),
             {lists:reverse(L), file_rterms(no_file, Files)};
         _Error ->
-            file:close(Fd),
+            _ = file:close(Fd),
             {error, {bad_term, FileName}}
     end;
 file_rterms2(Fd, L, _LSz, FileName, Files) ->
@@ -1568,7 +1574,7 @@ write_terms(Fd, F, [B | Bs], Args) ->
         ok -> 
             write_terms(Fd, F, Bs, Args);
         {error, Reason} ->
-            file:close(Fd),
+            _ = file:close(Fd),
             {error, {file_error, F, Reason}}
     end;
 write_terms(Fd, F, [], Args) ->
diff --git a/lib/stdlib/src/filelib.erl b/lib/stdlib/src/filelib.erl
index 42ef3679a2..42885bcdcf 100644
--- a/lib/stdlib/src/filelib.erl
+++ b/lib/stdlib/src/filelib.erl
@@ -231,7 +231,7 @@ ensure_dir(F) ->
 	    %% Protect against infinite loop
 	    {error,einval};
 	false ->
-	    ensure_dir(Dir),
+	    _ = ensure_dir(Dir),
 	    case file:make_dir(Dir) of
 		{error,eexist}=EExist ->
 		    case do_is_dir(Dir, file) of
diff --git a/lib/stdlib/src/gen_fsm.erl b/lib/stdlib/src/gen_fsm.erl
index d9411e58cf..e9654322f1 100644
--- a/lib/stdlib/src/gen_fsm.erl
+++ b/lib/stdlib/src/gen_fsm.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -549,7 +549,7 @@ handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time, Debug) ->
 	{stop, Reason, Reply, NStateData} when From =/= undefined ->
 	    {'EXIT', R} = (catch terminate(Reason, Name, Msg, Mod,
 					   StateName, NStateData, Debug)),
-	    reply(Name, From, Reply, Debug, StateName),
+	    _ = reply(Name, From, Reply, Debug, StateName),
 	    exit(R);
 	{'EXIT', What} ->
 	    terminate(What, Name, Msg, Mod, StateName, StateData, Debug);
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index 30a81ade49..4a16ed120f 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -623,7 +623,7 @@ handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, Debug) ->
 	{stop, Reason, Reply, NState} ->
 	    {'EXIT', R} = 
 		(catch terminate(Reason, Name, Msg, Mod, NState, Debug)),
-	    reply(Name, From, Reply, NState, Debug),
+	    _ = reply(Name, From, Reply, NState, Debug),
 	    exit(R);
 	Other ->
 	    handle_common_reply(Other, Parent, Name, Msg, Mod, State, Debug)
diff --git a/lib/stdlib/src/log_mf_h.erl b/lib/stdlib/src/log_mf_h.erl
index 19b555a48c..6b42363979 100644
--- a/lib/stdlib/src/log_mf_h.erl
+++ b/lib/stdlib/src/log_mf_h.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -135,7 +135,12 @@ handle_event(Event, State) ->
 			State#state{cur_fd = NewFd, curF = NewF, curB = 0}
 		end,
 	    [Hi,Lo] = put_int16(Size),
-	    file:write(NewState#state.cur_fd, [Hi, Lo, Bin]),
+            case file:write(NewState#state.cur_fd, [Hi, Lo, Bin]) of
+                ok ->
+                    ok;
+                {error, Reason} ->
+                    exit({file_exit, Reason})
+            end,
 	    {ok, NewState#state{curB = NewState#state.curB + Size + 2}};
 	_ ->
 	    {ok, State}
@@ -174,7 +179,7 @@ file_open(Dir, FileNo) ->
 	    write_index_file(Dir, FileNo),
 	    {ok, Fd};
 	_ -> 
-	    exit({file, open})
+	    exit(file_open)
     end.
 
 put_int16(I) ->
@@ -211,7 +216,7 @@ write_index_file(Dir, Index) ->
 	    ok = file:close(Fd),
 	    ok = file:rename(TmpFile,File),
 	    ok;
-	_ -> exit(open_index_file)
+	_ -> exit(write_index_file)
     end.
 
 inc(N, Max) ->
diff --git a/lib/stdlib/src/pool.erl b/lib/stdlib/src/pool.erl
index a5eb191ab2..dfe6318dea 100644
--- a/lib/stdlib/src/pool.erl
+++ b/lib/stdlib/src/pool.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2011. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -63,7 +63,7 @@ start(Name) ->
       Args :: string(),
       Nodes :: [node()].
 start(Name, Args) when is_atom(Name) ->
-    gen_server:start({global, pool_master}, pool, [], []),
+    _ = gen_server:start({global, pool_master}, pool, [], []),
     Hosts = net_adm:host_file(),
     Nodes = start_nodes(Hosts, Name, Args),
     lists:foreach(fun attach/1, Nodes),
diff --git a/lib/stdlib/src/shell.erl b/lib/stdlib/src/shell.erl
index c6c706c3a7..0d2fc47d13 100644
--- a/lib/stdlib/src/shell.erl
+++ b/lib/stdlib/src/shell.erl
@@ -58,7 +58,7 @@ start(NoCtrlG) ->
     start(NoCtrlG, false).
 
 start(NoCtrlG, StartSync) ->
-    code:ensure_loaded(user_default),
+    _ = code:ensure_loaded(user_default),
     spawn(fun() -> server(NoCtrlG, StartSync) end).
 
 %% Find the pid of the current evaluator process.
@@ -677,8 +677,10 @@ exprs([E0|Es], Bs1, RT, Lf, Ef, Bs0, W) ->
             if
                 Es =:= [] ->
                     VS = pp(V0, 1, RT),
-                    [io:requests([{put_chars, unicode, VS}, nl]) ||
-                        W =:= cmd],
+                    case W of
+                        cmd -> io:requests([{put_chars, unicode, VS}, nl]);
+                        pmt -> ok
+                    end,
                     %% Don't send the result back if it will be
                     %% discarded anyway.
                     V = if
diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl
index 54328cd9ff..26821e0e09 100644
--- a/lib/stdlib/src/supervisor.erl
+++ b/lib/stdlib/src/supervisor.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -260,7 +260,7 @@ init_children(State, StartSpec) ->
                 {ok, NChildren} ->
                     {ok, State#state{children = NChildren}};
                 {error, NChildren, Reason} ->
-                    terminate_children(NChildren, SupName),
+                    _ = terminate_children(NChildren, SupName),
                     {stop, {shutdown, Reason}}
             end;
         Error ->
@@ -752,7 +752,10 @@ restart(Child, State) ->
 		    Id = if ?is_simple(State) -> Child#child.pid;
 			    true -> Child#child.name
 			 end,
-		    timer:apply_after(0,?MODULE,try_again_restart,[self(),Id]),
+		    {ok, _TRef} = timer:apply_after(0,
+                                                    ?MODULE,
+                                                    try_again_restart,
+                                                    [self(),Id]),
 		    {ok,NState2};
 		{try_again, NState2, #child{name=ChName}} ->
 		    timer:apply_after(0,?MODULE,try_again_restart,[self(),ChName]),
@@ -850,7 +853,7 @@ terminate_children(Children, SupName) ->
 %% we do want them to be shut down as many functions from this module
 %% use this function to just clear everything.
 terminate_children([Child = #child{restart_type=temporary} | Children], SupName, Res) ->
-    do_terminate(Child, SupName),
+    _ = do_terminate(Child, SupName),
     terminate_children(Children, SupName, Res);
 terminate_children([Child | Children], SupName, Res) ->
     NChild = do_terminate(Child, SupName),
@@ -1008,7 +1011,7 @@ wait_dynamic_children(_Child, _Pids, 0, undefined, EStack) ->
 wait_dynamic_children(_Child, _Pids, 0, TRef, EStack) ->
 	%% If the timer has expired before its cancellation, we must empty the
 	%% mail-box of the 'timeout'-message.
-    erlang:cancel_timer(TRef),
+    _ = erlang:cancel_timer(TRef),
     receive
         {timeout, TRef, kill} ->
             EStack
diff --git a/lib/stdlib/src/sys.erl b/lib/stdlib/src/sys.erl
index bffeb44179..5359a6d5bc 100644
--- a/lib/stdlib/src/sys.erl
+++ b/lib/stdlib/src/sys.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %% 
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -320,7 +320,7 @@ handle_system_msg(SysState, Msg, From, Parent, Mod, Debug, Misc, Hib) ->
 	    gen:reply(From, Reply),
 	    suspend_loop(suspended, Parent, Mod, NDebug, NMisc, Hib);
 	{running, Reply, NDebug, NMisc} ->
-	    gen:reply(From, Reply),
+	    _ = gen:reply(From, Reply),
             Mod:system_continue(Parent, NDebug, NMisc)
     end.
 
diff --git a/lib/stdlib/src/timer.erl b/lib/stdlib/src/timer.erl
index e11fb046e9..72a2dd9616 100644
--- a/lib/stdlib/src/timer.erl
+++ b/lib/stdlib/src/timer.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2011. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -258,7 +258,7 @@ ensure_started() ->
 	undefined -> 
 	    C = {timer_server, {?MODULE, start_link, []}, permanent, 1000, 
 		 worker, [?MODULE]},
-	    supervisor:start_child(kernel_safe_sup, C),  % kernel_safe_sup
+	    _ = supervisor:start_child(kernel_safe_sup, C),
 	    ok;
 	_ -> ok
     end.