Mailing-List: contact commits-help@arrow.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@arrow.apache.org
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
From: wesm@apache.org
To: commits@arrow.apache.org
Message-Id: <015678de42d34ee6813d96cefcac5bcc@git.apache.org>
Subject: arrow git commit: ARROW-1401: [C++] Add note to readme about
 ARROW_EXTRA_ERROR_CONTEXT [Forced Update!]
Date: Tue,  5 Sep 2017 16:32:27 +0000 (UTC)
archived-at: Tue, 05 Sep 2017 16:32:30 -0000

Repository: arrow
Updated Branches:
  refs/heads/master 6e702f959 -> 1ba19c20c (forced update)


ARROW-1401: [C++] Add note to readme about ARROW_EXTRA_ERROR_CONTEXT

Change-Id: I1d1dad715e00d45479efce0239e9e1101b540e3b


Project: http://git-wip-us.apache.org/repos/asf/arrow/repo
Commit: http://git-wip-us.apache.org/repos/asf/arrow/commit/1ba19c20
Tree: http://git-wip-us.apache.org/repos/asf/arrow/tree/1ba19c20
Diff: http://git-wip-us.apache.org/repos/asf/arrow/diff/1ba19c20

Branch: refs/heads/master
Commit: 1ba19c20c518876b641c33ec14894d9079fced10
Parents: 3283d2a
Author: Wes McKinney <wes.mckinney@twosigma.com>
Authored: Tue Sep 5 12:29:51 2017 -0400
Committer: Wes McKinney <wes.mckinney@twosigma.com>
Committed: Tue Sep 5 12:32:12 2017 -0400

----------------------------------------------------------------------
 cpp/README.md | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/arrow/blob/1ba19c20/cpp/README.md
----------------------------------------------------------------------
diff --git a/cpp/README.md b/cpp/README.md
index f37ec03..993efb8 100644
--- a/cpp/README.md
+++ b/cpp/README.md
@@ -172,6 +172,28 @@ constructors, the circumstances where they would are somewhat esoteric, and it
 is likely that an application would have encountered other more serious
 problems prior to having `std::bad_alloc` thrown in a constructor.
 
+### Extra debugging help
+
+If you use the CMake option `-DARROW_EXTRA_ERROR_CONTEXT=ON` it will compile
+the libraries with extra debugging information on error checks inside the
+`RETURN_NOT_OK` macro. In unit tests with `ASSERT_OK`, this will yield error
+outputs like:
+
+
+```
+../src/arrow/ipc/ipc-read-write-test.cc:609: Failure
+Failed
+NotImplemented: ../src/arrow/ipc/ipc-read-write-test.cc:574 code: writer->WriteRecordBatch(batch)
+../src/arrow/ipc/writer.cc:778 code: CheckStarted()
+../src/arrow/ipc/writer.cc:755 code: schema_writer.Write(&dictionaries_)
+../src/arrow/ipc/writer.cc:730 code: WriteSchema()
+../src/arrow/ipc/writer.cc:697 code: WriteSchemaMessage(schema_, dictionary_memo_, &schema_fb)
+../src/arrow/ipc/metadata-internal.cc:651 code: SchemaToFlatbuffer(fbb, schema, dictionary_memo, &fb_schema)
+../src/arrow/ipc/metadata-internal.cc:598 code: FieldToFlatbuffer(fbb, *schema.field(i), dictionary_memo, &offset)
+../src/arrow/ipc/metadata-internal.cc:508 code: TypeToFlatbuffer(fbb, *field.type(), &children, &layout, &type_enum, dictionary_memo, &type_offset)
+Unable to convert type: decimal(19, 4)
+```
+
 ### Deprecations and API Changes
 
 We use the compiler definition `ARROW_NO_DEPRECATED_API` to disable APIs that