[stdlib] Fix a contract bug

Also minor corrections of the docs of io(3)

4 files changed, 52 insertions, 15 deletions

diff --git a/lib/stdlib/doc/src/io.xml b/lib/stdlib/doc/src/io.xml
index e904f0f0c8..67edc013d4 100644
--- a/lib/stdlib/doc/src/io.xml
+++ b/lib/stdlib/doc/src/io.xml
@@ -4,7 +4,7 @@
 <erlref>
   <header>
     <copyright>
-      <year>1996</year><year>2012</year>
+      <year>1996</year><year>2013</year>
       <holder>Ericsson AB. All Rights Reserved.</holder>
     </copyright>
     <legalnotice>
@@ -306,6 +306,11 @@
           <item>
             <p>The parsing failed.</p>
           </item>
+	  <tag><c>{error, <anno>ErrorDescription</anno>}</c></tag>
+	  <item>
+	    <p>Other (rare) error condition, for instance <c>{error, estale}</c>
+	    if reading from an NFS file system.</p>
+	  </item>
         </taglist>
       </desc>
     </func>
@@ -333,6 +338,11 @@
           <item>
             <p>The parsing failed.</p>
           </item>
+	  <tag><c>{error, <anno>ErrorDescription</anno>}</c></tag>
+	  <item>
+	    <p>Other (rare) error condition, for instance <c>{error, estale}</c>
+	    if reading from an NFS file system.</p>
+	  </item>
         </taglist>
       </desc>
     </func>
@@ -851,12 +861,21 @@ enter><input>:</input>   <input>alan</input>   <input>:</input>   <input>joe</in
           </item>
           <tag><c>{eof, EndLocation}</c></tag>
           <item>
-            <p>End of file was encountered.</p>
+            <p>End of file was encountered by the tokenizer.</p>
+          </item>
+          <tag><c>eof</c></tag>
+          <item>
+            <p>End of file was encountered by the I/O-server.</p>
           </item>
           <tag><c>{error, ErrorInfo, ErrorLocation}</c></tag>
           <item>
-            <p>An error occurred.</p>
+            <p>An error occurred while tokenizing.</p>
           </item>
+	  <tag><c>{error, <anno>ErrorDescription</anno>}</c></tag>
+	  <item>
+	    <p>Other (rare) error condition, for instance <c>{error, estale}</c>
+	    if reading from an NFS file system.</p>
+	  </item>
         </taglist>
         <p>Example:</p>
         <pre>
@@ -913,12 +932,21 @@ enter><input>1.0er.</input>
           </item>
           <tag><c>{eof, EndLocation}</c></tag>
           <item>
-            <p>End of file was encountered.</p>
+            <p>End of file was encountered by the tokenizer.</p>
+          </item>
+          <tag><c>eof</c></tag>
+          <item>
+            <p>End of file was encountered by the I/O-server.</p>
           </item>
           <tag><c>{error, ErrorInfo, ErrorLocation}</c></tag>
           <item>
-            <p>An error occurred.</p>
+            <p>An error occurred while tokenizing or parsing.</p>
           </item>
+	  <tag><c>{error, <anno>ErrorDescription</anno>}</c></tag>
+	  <item>
+	    <p>Other (rare) error condition, for instance <c>{error, estale}</c>
+	    if reading from an NFS file system.</p>
+	  </item>
         </taglist>
         <p>Example:</p>
         <pre>
@@ -955,12 +983,21 @@ enter><input>abc("hey".</input>
           </item>
           <tag><c>{eof, EndLocation}</c></tag>
           <item>
-            <p>End of file was encountered.</p>
+            <p>End of file was encountered by the tokenizer.</p>
+          </item>
+          <tag><c>eof</c></tag>
+          <item>
+            <p>End of file was encountered by the I/O-server.</p>
           </item>
           <tag><c>{error, ErrorInfo, ErrorLocation}</c></tag>
           <item>
-            <p>An error occurred.</p>
+            <p>An error occurred while tokenizing or parsing.</p>
           </item>
+	  <tag><c>{error, <anno>ErrorDescription</anno>}</c></tag>
+	  <item>
+	    <p>Other (rare) error condition, for instance <c>{error, estale}</c>
+	    if reading from an NFS file system.</p>
+	  </item>
         </taglist>
       </desc>
     </func>
diff --git a/lib/stdlib/src/io.erl b/lib/stdlib/src/io.erl
index ecf2aeb375..9b436c224c 100644
--- a/lib/stdlib/src/io.erl
+++ b/lib/stdlib/src/io.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
@@ -331,7 +331,7 @@ fread(Prompt, Format) ->
       Prompt :: prompt(),
       Format :: format(),
       Result :: {'ok', Terms :: [term()]}
-              | {'error', FreadError :: io_lib:fread_error()}
+              | {'error', {'fread', FreadError :: io_lib:fread_error()}}
               | server_no_data().
 
 fread(Io, Prompt, Format) ->
diff --git a/lib/stdlib/src/io_lib.erl b/lib/stdlib/src/io_lib.erl
index 5ad505f683..df5f9b8c25 100644
--- a/lib/stdlib/src/io_lib.erl
+++ b/lib/stdlib/src/io_lib.erl
@@ -2,7 +2,7 @@
 %%
 %% %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
@@ -124,7 +124,7 @@ fwrite(Format, Args) ->
               | {'more', RestFormat :: string(),
                  Nchars :: non_neg_integer(),
                  InputStack :: chars()}
-              | {'error', What :: fread_error()}.
+              | {'error', {'fread', What :: fread_error()}}.
 
 fread(Chars, Format) ->
     io_lib_fread:fread(Chars, Format).
@@ -137,7 +137,7 @@ fread(Chars, Format) ->
               | {'done', Result, LeftOverChars :: string()},
       Result :: {'ok', InputList :: [term()]}
               | 'eof'
-              | {'error', What :: fread_error()}.
+              | {'error', {'fread', What :: fread_error()}}.
 
 fread(Cont, Chars, Format) ->
     io_lib_fread:fread(Cont, Chars, Format).
diff --git a/lib/stdlib/src/io_lib_fread.erl b/lib/stdlib/src/io_lib_fread.erl
index 84d4b8bba0..92a34995b8 100644
--- a/lib/stdlib/src/io_lib_fread.erl
+++ b/lib/stdlib/src/io_lib_fread.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
@@ -22,7 +22,7 @@
 
 -export([fread/2,fread/3]).
 
--import(lists, [reverse/1,reverse/2]).
+-import(lists, [reverse/1]).
 
 -define(is_whitespace(C),
 	((C) =:= $\s orelse (C) =:= $\t
@@ -43,7 +43,7 @@
               | {'done', Result, LeftOverChars :: string()},
       Result :: {'ok', InputList :: io_lib:chars()}
               | 'eof'
-              | {'error', What :: io_lib:fread_error()}.
+              | {'error', {'read', What :: io_lib:fread_error()}}.
 
 fread([], Chars, Format) ->
     %%io:format("FREAD: ~w `~s'~n", [Format,Chars]),