Mailing-List: contact stdcxx-dev-help@incubator.apache.org; run by ezmlm
Precedence: bulk
Reply-To: stdcxx-dev@incubator.apache.org
Received-SPF: neutral (asf.osuosl.org: local policy)
Message-ID: <44D7AC85.3070107@roguewave.com>
Date: Mon, 07 Aug 2006 15:11:33 -0600
From: Andrew Black <ablack@roguewave.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US;
 rv:1.8.0.5) Gecko/20060720 SeaMonkey/1.0.3
MIME-Version: 1.0
To: stdcxx-dev@incubator.apache.org
Subject: [patch]Re: examples in OUTPUT state
References: <44D3F3FC.8070007@roguewave.com>
In-Reply-To: <44D3F3FC.8070007@roguewave.com>
Content-Type: multipart/mixed;
 boundary="------------050600020000060900090900"

--------------050600020000060900090900
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Greetings all.

Attached is a short patch that should resolve this issue.

The cause of the error was that the output was smaller than the static 
holding buffer, so the call to memcmp was comparing beyond the amount of 
data that had been read into the buffer.  This in turn was leading to a 
difference in the unfilled portions of the buffer.  This difference was 
caused by the natural variations in uninitialized memory.

--Andrew Black

Martin Sebor wrote:
> There are a bunch of examples that the exec utility reports as
> having failed with the OUTPUT status even though when executed
> by hand they run successfully to completion and produce the
> expected output. I suspect there must be a bug in the utility.
> 
> $ make auto_ptr run; ./auto_ptr > auto_ptr.out && diff auto_ptr.out 
> /build/sebor/stdcxx/examples/manual/out/auto_ptr.out; echo $?
> make: `auto_ptr' is up to date.
> NAME                      STATUS ASSERTS FAILED PERCNT
> auto_ptr                  OUTPUT
> 0
> 
> Martin

--------------050600020000060900090900
Content-Type: text/x-patch;
 name="shortdelta.diff"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="shortdelta.diff"

Index: output.cpp
===================================================================
--- output.cpp	(revision 429465)
+++ output.cpp	(working copy)
@@ -296,6 +296,10 @@
         size_t out_read, ref_read;
         int match = 1;
 
+        /* Zero out holding buffers to avoid false differences */
+        memset (out_buf, 0, DELTA_BUF_LEN);
+        memset (ref_buf, 0, DELTA_BUF_LEN);
+
         while (!feof (reference) && !feof (output)) {
             /* First, read a block from the files into the buffer */
             out_read = fread (out_buf, DELTA_BUF_LEN, 1, output);

--------------050600020000060900090900--