Hello concurrent world

Frances Buontempo from BuontempoConsulting


From Anthony William's "C++ concurrency in action - practical multithreading", section 1.4.1 gives a simple "Hello world" program using C++11's thread.

#include <iostream>
#include <thread>

void hello()
{
std::cout <<"Hello concurrent world!\n";
}


int main()
{
std::thread t(hello);
t.join();
}


After Matthew Wilson re-starting his series in Overload, "Quality Matters #7 Exceptions: the story so far" http://accu.org/var/uploads/journals/Overload114.pdf page 10ff, I had a nagging feeling I should put some exception handling round this.

First question, what happens if we make the hello throw an exception? For example, what would this do?

std::thread t_trouble( []{ throw std::exception("Oops");} );

It calls abort. The thread function mustn't let exceptions escape. Also, main should probably catch some exceptions; for example, maybe there aren't enough resources to start the thread yet.

#include <iostream>
#include <thread>

void hello()
{
try
{
std::cout <<"Hello concurrent world!\n";
}
catch(const std::exception& e)
{
//erm... what to do with it?
}
}


int main()
{
try
{
std::thread t(hello);//can I pass parameters? Nico says I can to async (page 964)
t.join(); //Nico says we can do a t.detach and when main exits it will get stopped
}
catch(const std::system_error& e) //pulled in by thread I presume
{
if(e.code() == std::errc::resource_unavailable_try_again)
{
std::cout << "Try again\n";
}
}
catch(const std::exception& e)
{
std::cout << e.what() << '\n';
}
}

Right, so now we are ignoring any exceptions that get thrown.
What should I do with any exceptions I get in a function that's sent to a thread? I could use std::exception_ptr, and std::rethrow_exception when a client tries to get the result. It might be better if I read all of Anthony's book (esp Chapter 8) and use std::packaged_task instead.

accu-general (http://accu.org/index.php/mailinglists) helpfully told me to read all the chapters in the book concurrently.

Writing: Bug Hunting

Pete Goodliffe from Pete Goodliffe

The latest  C Vu magazine from ACCU is out now. It contains my latest Becoming a Better Programer column. This month it's called Bug Hunting and, as you might guess, is about the art of debugging code.

This was inspired by conversations with Greg Law in the lead up to the 2013 ACCU conference.

About a month without Google Reader

The Lone C++ Coder's Blog from The Lone C++ Coder&#039;s Blog

As a bit of an RSS junkie - see previous post - I had to go look for alternatives to Google Reader. I’ve been a feedly user on and off for a few years but I was never that taken with it. It does seem to do mostly do what it says on the tin and having various tablet apps available for feedly is a good thing, but it tends to run into a few issues with high-volume feeds (craigslist feeds, I’m looking at you).

Visual Lint and Windows Driver Kit (WDK) projects

Products, the Universe and Everything from Products, the Universe and Everything

We have recently been working with Don Burn on PC-lint analysis of Windows Driver Kit (WDK) projects, and he has written an interesting article on the subject titled "Another Look at Lint" in the March-April 2013 issue of the NT Insider.

Within the article you will find the following rather complementary passage:

Finally the ultimate tool for using PC-lint with the WDK is Riverblade's Visual Lint. This is a third party tool providing an integrated package that works inside VS2012. The tool is an add-on to PC-lint which you must still purchase. The capabilities include background analysis of the project, coded display listings that - like Visual Studio - clicking on the error takes you to the line to edit and provides easy lookup of the description of the errors. The latest version of Visual Lint (4.0.2.198) is required for use with the WDK. The tool has a minor bug that if there are two subprojects with the same name, such as filter in the Toaster sample, one needs to be renamed for analysis to work. A fix is in the works.

To use Visual Lint with the WDK choose LintLdx.lnt as the standard lint configuration file for the tool. There is a 30-day free trial of Visual Lint available so if you are considering PC-lint, take a look at what Visual Lint can add to the experience. I expect to be using it for much of my work.

Our thanks to Don Burn for his patience while we worked through the issues raised by the analysis of WDK projects. As a postscript, a fix for the bug he refers to above has already been checked in and should become available in the next public Visual Lint build (most likely 4.0.3.200).

Visual Lint and Windows Driver Kit (WDK) projects

Products, the Universe and Everything from Products, the Universe and Everything

We have recently been working with Don Burn on PC-lint analysis of Windows Driver Kit (WDK) projects, and he has written an interesting article on the subject titled "Another Look at Lint" in the March-April 2013 issue of the NT Insider.

Within the article you will find the following rather complementary passage:

Finally the ultimate tool for using PC-lint with the WDK is Riverblade's Visual Lint. This is a third party tool providing an integrated package that works inside VS2012. The tool is an add-on to PC-lint which you must still purchase. The capabilities include background analysis of the project, coded display listings that - like Visual Studio - clicking on the error takes you to the line to edit and provides easy lookup of the description of the errors. The latest version of Visual Lint (4.0.2.198) is required for use with the WDK. The tool has a minor bug that if there are two subprojects with the same name, such as filter in the Toaster sample, one needs to be renamed for analysis to work. A fix is in the works.

To use Visual Lint with the WDK choose LintLdx.lnt as the standard lint configuration file for the tool. There is a 30-day free trial of Visual Lint available so if you are considering PC-lint, take a look at what Visual Lint can add to the experience. I expect to be using it for much of my work.

Our thanks to Don Burn for his patience while we worked through the issues raised by the analysis of WDK projects. As a postscript, a fix for the bug he refers to above has already been checked in and should become available in the next public Visual Lint build (most likely 4.0.3.200).

Visual Lint and Windows Driver Kit (WDK) projects

Products, the Universe and Everything from Products, the Universe and Everything

We have recently been working with Don Burn on PC-lint analysis of Windows Driver Kit (WDK) projects, and he has written an interesting article on the subject titled "Another Look at Lint" in the March-April 2013 issue of the NT Insider.

Within the article you will find the following rather complementary passage:

Finally the ultimate tool for using PC-lint with the WDK is Riverblade's Visual Lint. This is a third party tool providing an integrated package that works inside VS2012. The tool is an add-on to PC-lint which you must still purchase. The capabilities include background analysis of the project, coded display listings that - like Visual Studio - clicking on the error takes you to the line to edit and provides easy lookup of the description of the errors. The latest version of Visual Lint (4.0.2.198) is required for use with the WDK. The tool has a minor bug that if there are two subprojects with the same name, such as filter in the Toaster sample, one needs to be renamed for analysis to work. A fix is in the works.

To use Visual Lint with the WDK choose LintLdx.lnt as the standard lint configuration file for the tool. There is a 30-day free trial of Visual Lint available so if you are considering PC-lint, take a look at what Visual Lint can add to the experience. I expect to be using it for much of my work.

Our thanks to Don Burn for his patience while we worked through the issues raised by the analysis of WDK projects. As a postscript, a fix for the bug he refers to above has already been checked in and should become available in the next public Visual Lint build (most likely 4.0.3.200).

Visual Lint and Windows Driver Kit (WDK) projects

Products, the Universe and Everything from Products, the Universe and Everything

We have recently been working with Don Burn on PC-lint analysis of Windows Driver Kit (WDK) projects, and he has written an interesting article on the subject titled "Another Look at Lint" in the March-April 2013 issue of the NT Insider. Within the article you will find the following rather complementary passage:
Finally the ultimate tool for using PC-lint with the WDK is Riverblade's Visual Lint. This is a third party tool providing an integrated package that works inside VS2012. The tool is an add-on to PC-lint which you must still purchase. The capabilities include background analysis of the project, coded display listings that - like Visual Studio - clicking on the error takes you to the line to edit and provides easy lookup of the description of the errors. The latest version of Visual Lint (4.0.2.198) is required for use with the WDK. The tool has a minor bug that if there are two subprojects with the same name, such as filter in the Toaster sample, one needs to be renamed for analysis to work. A fix is in the works. To use Visual Lint with the WDK choose LintLdx.lnt as the standard lint configuration file for the tool. There is a 30-day free trial of Visual Lint available so if you are considering PC-lint, take a look at what Visual Lint can add to the experience. I expect to be using it for much of my work.
Our thanks to Don Burn for his patience while we worked through the issues raised by the analysis of WDK projects. As a postscript, a fix for the bug he refers to above has already been checked in and should become available in the next public Visual Lint build (most likely 4.0.3.200).

Of course I have to post something about Google Reader, too

The Lone C++ Coder's Blog from The Lone C++ Coder&#039;s Blog

The demise of Google reader viewed from a slightly different perspective. I find the analysis from someone who isn’t a proto-geek but rather an investment professional interesting, mainly because there are insights that some like me - who doesn’t spend the whole day looking at companies and trying to figure out what they are doing as opposed to what they say they are doing - would and this case, have missed.

If you’re using boost::variant, you need to have a look at Boost 1.53

The Lone C++ Coder's Blog from The Lone C++ Coder&#039;s Blog

I was profiling some code a while ago that makes extensive use of boost::variant and one of the lessons from the profiler run was that boost variants appear to be fairly expensive to construct and copy. As of 1.53, variants support rvalue constructors and rvalue assignment operators. My initial measurements suggest that when used with types that are “move enabled”, there is a benefit in upgrading to this version of boost variant, both in performance and memory consumption.

Improving the Emacs integration in Windows

The Lone C++ Coder's Blog from The Lone C++ Coder&#039;s Blog

I was trying to make Windows a little more Emacs-friendly (or was it the other way around?). First step was to enable the emacs server in my .emacs so I could make use of Emacs for quick and dirty editing tasks that require an editor better than Notepad but where the average Emacs startup time was just a little too long to make Emacs a viable alternative. A typical example would be to use Emacs as the editor for commit messages in Mercurial.