Channel 9 - Discussions by Matt_PD http://mschnlnine.vo.llnwd.net/d1/Dev/App_Themes/C9/images/feedimage.png Channel 9 - Discussions by Matt_PD http://channel9.msdn.com/Niners/Matt_PD/Discussions Channel 9 keeps you up to date with the latest news and behind the scenes info from Microsoft that developers love to keep up with. From LINQ to SilverLight – Watch videos and hear about all the cool technologies coming and the people behind them. http://channel9.msdn.com/Niners/Matt_PD/Discussions en Fri, 24 May 2013 11:46:10 GMT Fri, 24 May 2013 11:46:10 GMT Rev9 0 0 0 Tech Off - Andrei, Herb and Scott: Got C++11 Questions? I've got a question regarding a (future, potential) metaprogramming facility -- namely, a possibility of standardizing static loops. It might go hand in hand with adding static conditional expressions (like the proposed static_if) to the future versions of the standard.

The practical (example) context is Section 15 Metaprogramming of the Agner's optimization manual, "Optimizing software in C++: An optimization guide for Windows, Linux and Mac platforms", see http://www.agner.org/optimize/optimizing_cpp.pdf & http://www.agner.org/optimize/#manuals.

In particular, it discusses examples that "explain how metaprogramming can be used to speed up the calculation of the power function when the exponent is an integer known at compile time."

"In C++ template metaprogramming, loops are implemented as recursive templates.

[...]

Why is template metaprogramming so complicated? Because the C++ template feature was
never designed for this purpose. It just happened to be possible.

[...]

The D language allows compile-time if statements (called static if), but no compile-
time loops. We can only hope that such a feature becomes available in the future. If a future
version of C++ should allow compile-time if and compile-time while loops, then the
transformation of example 15.1b to metaprogramming would be straightforward. The MASM
assembly language has full metaprogramming features, including the ability to define
function names and variable names from string functions. A metaprogramming
implementation analogous to example 15.1b and d in assembly language is provided as an
example in the "Macro loops" chapter in manual 2: "Optimizing subroutines in assembly
language"."

Right now we can (awkwardly) implement conditionals using template specialization and loops using recursive template instantiation.
I understand the proposed static_if facility is intended to avoid the awkwardness in the case of the compile-time if statements.
Would it be possible for the next revision of the standard to get an analogous (as described above) compile-time loops extension?

]]> http://channel9.msdn.com/Forums/TechOff/Andrei-Herb-and-Scott-Got-C11-Questions/6947394a1f5845f18c7aa0a2015f6972#6947394a1f5845f18c7aa0a2015f6972 Fri, 03 Aug 2012 21:19:27 GMT http://channel9.msdn.com/Forums/TechOff/Andrei-Herb-and-Scott-Got-C11-Questions/6947394a1f5845f18c7aa0a2015f6972#6947394a1f5845f18c7aa0a2015f6972 Matt 10 http://channel9.msdn.com/Niners/Matt_PD/Discussions/RSS Tech Off - _ITERATOR_DEBUG_LEVEL error converting VC++6.0 to VC++ 2010 @daEliteSniper: Right-click your Solution in the Solution Explorer, go to Configuration Properties, then Configuration, make sure that all of the projects have the same Configuration settings (i.e., no mixing of Debug / Release Configurations). Having make sure of that, try to Rebuild Solution (Ctrl+Alt+F7).

]]> http://channel9.msdn.com/Forums/TechOff/ITERATORDEBUGLEVEL-error-converting-VC60-to-VC-2010/eab6a9bb0255496a8cdc9fb2014d3ecc#eab6a9bb0255496a8cdc9fb2014d3ecc Wed, 07 Dec 2011 20:13:18 GMT http://channel9.msdn.com/Forums/TechOff/ITERATORDEBUGLEVEL-error-converting-VC60-to-VC-2010/eab6a9bb0255496a8cdc9fb2014d3ecc#eab6a9bb0255496a8cdc9fb2014d3ecc Matt 5 http://channel9.msdn.com/Niners/Matt_PD/Discussions/RSS Tech Off - _ITERATOR_DEBUG_LEVEL error converting VC++6.0 to VC++ 2010 It looks like you're attempting to link object files built with different _ITERATOR_DEBUG_LEVEL (IDL) settings -- since the standard library / run-time libs versions linked with different IDL settings are not mutually compatible, this won't work. Try rebuilding the entire solution, making sure (in the configuration/properties) that the debug/release setting are consistent throughout all of its projects.

For more info on what _ITERATOR_DEBUG_LEVEL is and what it does, see:

http://blogs.msdn.com/b/vcblog/archive/2011/04/05/10150198.aspx

http://channel9.msdn.com/Shows/Going+Deep/C9-Lectures-Stephan-T-Lavavej-Advanced-STL-3-of-n

 

]]> http://channel9.msdn.com/Forums/TechOff/ITERATORDEBUGLEVEL-error-converting-VC60-to-VC-2010/b5cb5a4cb1154d24b0a29fb20037d3dd#b5cb5a4cb1154d24b0a29fb20037d3dd Wed, 07 Dec 2011 03:23:15 GMT http://channel9.msdn.com/Forums/TechOff/ITERATORDEBUGLEVEL-error-converting-VC60-to-VC-2010/b5cb5a4cb1154d24b0a29fb20037d3dd#b5cb5a4cb1154d24b0a29fb20037d3dd Matt 5 http://channel9.msdn.com/Niners/Matt_PD/Discussions/RSS Tech Off - Advanced STL topics @STL: For me it'd be interesting to have a discussion of C++11 generic programming (GP) and template meta-programming (TMP) applied to design. C++11 introduced a couple of new features, like constexpr and enable_if that make GP & TMP more user-friendly.

My favorite project would be a multi-lecture series on topics in "Modern C++ Design: Generic Programming and Design Patterns Applied" by Andrei Alexandrescu and a discussion on what's a "Modern C++11 Design" way. If that's too ambitious, perhaps a good single-lecture would be to cover Chapter 1, Policy-Based Class Design, with full use of newly introduced C++11 features to achieve more expressive/simpler/higher-performing code?

This is sort of along the lines of Herb Sutter writing a few new (or updated) Guru of the Week Items for the C++11 era. Smiley

]]> http://channel9.msdn.com/Forums/TechOff/Advanced-STL-topics/c7dc510aed2142639e509fb0016c52c6#c7dc510aed2142639e509fb0016c52c6 Mon, 05 Dec 2011 22:06:27 GMT http://channel9.msdn.com/Forums/TechOff/Advanced-STL-topics/c7dc510aed2142639e509fb0016c52c6#c7dc510aed2142639e509fb0016c52c6 Matt 10 http://channel9.msdn.com/Niners/Matt_PD/Discussions/RSS