Boost C++ Libraries: Ticket #1574: operator<< for boost::posix_time::ptime ignores ostream flags

version changed

christian.stimming@… — Mon, 07 Jun 2010 09:24:29 GMT

version Boost 1.34.1 → Boost 1.43.0

I second this bug. The error still exists in boost-1.43.0. I'll attach a test case and a patch that fixes the bug by querying ostream::fail() before doing anything in the operator<<.

attachment set

christian.stimming@… — Mon, 07 Jun 2010 09:26:01 GMT

attachment → ptime-operator.cpp

Test case for this bug: Due to the error, in the second line the date still appears even though it shouldn't have been printed because of the ios::failbit.

attachment set

christian.stimming@… — Mon, 07 Jun 2010 09:26:47 GMT

attachment → fix-ptime-operator-bug1574.patch

Patch for fixing this bug by querying ostream::fail() before doing anything in the operator<< of ptime and time_duration

attachment set

christian.stimming@… — Mon, 07 Jun 2010 09:45:18 GMT

attachment → fix-ptime-operator-2nd-bug1574.patch

Better patch for this error which (after reading my Stroustrup again) is using the ostream's sentry constructor to check for potential failbits.

type changed

Katie Chan — Mon, 07 Jun 2010 23:00:01 GMT

type Bugs → Patches

Katie Chan — Thu, 02 Dec 2010 06:01:50 GMT

The most recent patch when applied to 1.45 does not produce the "expected output".

type changed

Katie Chan — Thu, 02 Dec 2010 06:02:38 GMT

type Patches → Bugs

christian.stimming@… — Tue, 21 Dec 2010 13:18:51 GMT

I don't understand ktchan's comment here. When compiling the attached example ptime-operator.cpp with any current boost (1.43, 1.45, SVN trunk; it doesn't matter which one), the output is

Should appear: Text. And Date: 2010-Dec-21 14:12:24.398138 Boost v104300
2010-Dec-21 14:12:24.398138
This line should appear (but no single date above): Text. And Date: 2010-Dec-21 14:12:24.398138

which is erroneous - the second line should have been empty. After applying the attached second patch fix-ptime-operator-2nd-bug1574.patch, the output is

Should appear: Text. And Date: 2010-Dec-21 14:12:32.328110 Boost v104300
This line should appear (but no single date above): Text. And Date: 2010-Dec-21 14:12:32.328110

which is the correct and expected output. Can you please apply the patch?

version, type changed

christian.stimming@… — Tue, 21 Dec 2010 13:19:48 GMT

version Boost 1.43.0 → Boost 1.45.0
type Bugs → Patches

Katie Chan — Tue, 21 Dec 2010 17:27:10 GMT

Hmm, my bad. I swear that when I tested it last time round, the output wasn't what was expected. :?

Rob Stewart — Thu, 13 Jan 2011 12:57:22 GMT

The patch looks good except for the ill-formed identifiers with double underscores. I also find "cerb" to be nonsensical. The following changes would be better:

Instead of:

typedef std::basic_ostream<CharT, TraitsT> __ostream_type;
typename __ostream_type::sentry cerb(os);
if (cerb)

Use this:

typename std::basic_ostream<CharT, TraitsT>::sentry ready(os);
if (ready)

christian.stimming@… — Thu, 13 Jan 2011 15:34:23 GMT

Feel free to commit the patch in the changed form you explained. However, the form I submitted was copied verbatim from gcc's STL, on Linux available in the file /usr/include/c++/4.4/bits/ostream_insert.h line 77ff.

I don't know specific reasons for choosing the form I copied from there, so feel free to implement it differently in boost. But if you ask me, I'd stick to the form proposed by gcc's STL.

Steven Watanabe — Thu, 13 Jan 2011 18:26:01 GMT

The reason the STL uses is exactly the reason that we can't use it. Identifiers containing a double underscore are reserved to the implementation (i.e. the compiler and standard library) for any use.

Dean Michael Berris — Mon, 31 Jan 2011 14:07:57 GMT

After looking at the ticket comments above I've made some modifications to make it a little more palatable playing nicely with the standard's forbidding the use of double underscores in identifiers that are not defined by the implementation. Please see the attached new modified patch.

attachment set

Dean Michael Berris — Mon, 31 Jan 2011 14:09:02 GMT

attachment → boost-date_time-1574.patch

Applies cleanly to trunk 68583

christian.stimming@… — Fri, 23 Mar 2012 09:08:08 GMT

Error still present in boost-1.46 and also still SVN trunk. Any news on applying the patch?

christian.stimming@… — Thu, 10 Jan 2013 10:20:21 GMT

Error still present in boost-1.52 and also still SVN trunk. Any news on applying the patch?

christian.stimming@… — Thu, 24 Oct 2013 11:10:51 GMT

Error still present in boost-1.53 and also still SVN trunk. Any news on applying the patch?