Friday, June 08, 2012

Nerd Food: Installing Wine Unstable on Debian Testing

Nerd Food: Installing Wine Unstable on Debian Testing

So it seems we're still on Wine 1.2 on Debian Testing. In Wine terms that's like really old. WineHQ does point to a site which has recent builds of Wine unstable for sid, so I thought I'd install them. Unfortunately, the chap doesn't provide an apt-gettable repository - by design, it seems - so we need to do it the hard way.

Before you start, make sure you have no remnants of a wine install. I found that these debs are not side-by-side installable with the previous version, so I removed all of wine from synaptic. If, on the steps below you see errors like this, then you still have an old installation of wine:

conflicting packages - not installing libwine-alsa-unstable

You have been warned. The first step is to get all the debs. I'm on Intel 64-bit so I grabbed the AMD-64 build. If you're on Intel 32-bit, be sure to download the correct i386 packages. For 64-bit just do:

mkdir wine_1.5.5
cd wine_1.5.5

To install them su to root and dpkg them in the correct order (well, a correct order I guess):

dpkg -i libwine-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-alsa-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-bin-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-capi-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-cms-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-gl-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-gphoto2-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-ldap-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-openal-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-oss-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-sane-unstable_1.5.5-0.1_amd64.deb
dpkg -i wine-bin-unstable_1.5.5-0.1_amd64.deb
dpkg -i libwine-print-unstable_1.5.5-0.1_amd64.deb
dpkg -i wine-unstable_1.5.5-0.1_amd64.deb

That's it! We can now run wine:

$ wine --version

Interestingly, whilst apps ran just fine and sound worked out of the box, I found myself unable to use the video camera. Apparently this is due to some issue with v4l:

The v4l headers were not available at compile time,
so video capture support is not available.

This requires some investigation.

Date: 2012-06-08 12:12:27 BST

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Thursday, June 07, 2012

Nerd Food: C++-11 with GCC

Nerd Food: C++-11 with GCC

Standard Disclaimer: as with all posts in Nerd Food, this is a summary of my notes and experience on the subject. Its likely there will be incorrect bits of information so don't start building your personal nuclear power station using this article. Or if you do, don't blame me.

Compiling a compiler has become a necessity for all of us living in the bleeding edge of C++-11. After all, who wants to wait for the next stable release of INSERT_FAVOURITE_COMPILER and then for INSERT_FAVOURITE_DISTRIBUTOR to start packaging them! We've already covered how to build and install Clang from source and use it to compile and run a trivial hello world; it seems only fitting to do the same thing for GCC.

A couple of notes on the content that follows:

  • the post focuses more on Linux but we also try to give some pointers for Windows (MinGW) and MacOSX. Testing was done on Windows XP and OSX Lion respectively.
  • we're targeting version 4.7 but you should be able to apply these instructions to svn trunk builds too - assuming you have the correct versions of the dependencies. We may cover that specific scenario on a later post.
  • we are - of course - assuming that you are using an older version of GCC to build GCC. You could try to use Clang or another compiler, but we didn't.


Rather unfortunately, one of the requirements for building a compiler is a working compiler. In addition, there is always a bit of fiddling required. Lets go through each platform in turn.

Debian Testing

Debian is going through the multi-arch transition at the moment, which complicates things. For instance, for reasons unknown we need to install 32-bit glibc development headers - even when building on 64-bit. The easiest way to do so is to install multi-platform support for the system GCC:

sudo apt-get install g++-multilib

In addition, its probably best to set the LIBRARY_PATH so we can tell the linker about it:

export LIBRARY_PATH=/usr/lib/x86_64-linux-gnu

If you don't, you'll probably experience weird C runt-time errors:

/usr/bin/ld: cannot find crt1.o: No such file or directory
/usr/bin/ld: cannot find crti.o: No such file or directory
collect2: ld returned 1 exit status


Grab XCode - or even better, just the Command Line Tools bundle - and make sure its installed and working. If all has gone well, the following should work when you open up a terminal:

gcc --version


We need to get a compiler on Windows before we can compile. We'll only cover the MinGW scenario. First get the main installer from MinGW and run it. During the setup choose the following options:

  • Repository catalogues: download latest repository catalogues.
  • Set destination location: Choose something like C:\MinGWRoot. The post-fix root is actually important because we will use c:\mingw later. Basically, choose any name other than \mingw on the chosen given drive.
  • Select Components: make sure "C Compiler", "C++ Compiler", "MSYS Basic System" and "MinGW Developer Toolkit" are ticked.

Click install and wait - it will take a while as it downloads all the packages. When finished, start the MinGW shell from the Start Menu and make sure the following works:

gcc --version

The next thing to do - a bit of a hack really - is to create an "identity" "mount". This is another way of saying that the MSYS1 root is actually the same as the windows root. The "cleanest" way to do this is to use junction which you can easily grab from SysInternals:

mingw-get install msys-wget
junction c:\\mingw C://MinGWRoot/msys/1.0

Now set the linker path pointing it to the identity mount:

export LIBRARY_PATH="/mingw/lib"

If you don't, you may experience the following error:

C:\MinGWRoot\mingw32\bin\ld.exe: cannot find dllcrt2.o: No such file or directory
collect2.exe: error: ld returned 1 exit status
make[3]: *** [libgcc_s.dll] Error 1
make[3]: Leaving directory `/home/marco/gcc-4.7.0_obj/i686-pc-mingw32/libgcc'

Building and Installing

Let's get started with the actual compilation. First we need to install the dependencies; you can peruse the prerequisites page for more details. I'm normally lazy and go with GMP, MPFR and MPC. This means we're not getting all the Graphite goodies which require PPL2.

The correct order of dependencies is as follows: GCC depends on MPC, which depends on MPFR, which depends on GMP; so the order of installation is:

  • GMP
  • MPFR
  • MPC
  • GCC

So we start by installing GMP (replace the --jobs 2 flag with the number of cores available on your machine):

tar xjf gmp-5.0.4.tar.bz2
cd gmp-5.0.4
./configure --prefix=${HOME}/local
make --jobs 2
make install
cd ..

If you are on a recent version of Linux you can use the brand-spanking xaf incantation of tar, which unpacks any archive type; in the interest of backwards compatibility we're sticking with the old invocations here.

Now we can install MPFR:

tar xjf mpfr-3.1.0.tar.bz2
cd mpfr-3.1.0
./configure --prefix=${HOME}/local --with-gmp=${HOME}/local
make --jobs 2
make install
cd ..

Note that we are using --with-gmp instead of using the traditional CFLAGS and LDFLAGS. This is a pattern followed through on GCC configuration; I highly recommend you follow it as I'm sure a lot of other things are happening on the background other than setting those environment variables. In fact you may want to even make sure these variables are not set to avoid any weird compilation problems.

MPC is installed next:

tar xf mpc-0.9.tar.gz
cd mpc-0.9
./configure --prefix=${HOME}/local --with-gmp=${HOME}/local \
make --jobs 2
make install
cd ..

Finally, we can now install GCC. Up til now we've been lazy and done in-source builds. This is normally frowned upon, but doesn't have any major consequences - that is, with the exception of GCC. The documentation states explicitly that this is not a good idea:

First, we highly recommend that GCC be built into a separate directory from the sources which does not reside within the source tree. This is how we generally build GCC; building where srcdir == objdir should still work, but doesn't get extensive testing; building where objdir is a subdirectory of srcdir is unsupported.

We're not that brave so we'll follow the recommendation. We compile GCC as follows:

tar xjf gcc-4.7.0.tar.bz2
mkdir gcc-4.7.0_obj
cd gcc-4.7.0_obj
../gcc-4.7.0/configure --prefix=${HOME}/local \
--enable-ld=yes --disable-nls --with-gmp=${HOME}/local \
--with-mpfr=${HOME}/local --with-mpc=${HOME}/local \
--program-suffix=-4.7 --enable-checking=release --enable-languages=c,c++
make --jobs 2
make install

Lets see in detail the more important GCC configuration options:

  • disable-nls: unless you are into internationalisation, you don't really need NLS. This shaves off a bit of build time.
  • enable-checking: lets make a few checks - no one wants a compiler that generates broken code.
  • enable-languages: we are only interested in C/C++, so no point in building ADA, Java, etc.
  • enable-ld: we're being old-school here and using traditional ld instead of gold, the new linker written in C++.

On the whole, these basic instructions are sufficient to build GCC on Linux, MacOSX and Windows (MinGW). However, when you leave Linux there is always a bit of platform-specific fiddling required. And to be fair, Debian testing also had a couple of wrinkles.

Compiling Hello World

In order to prove that we have a valid setup, lets create a trivial hello world, with a hint of C++-11:

#include <iostream>

int main(void) {
    auto hello = std::string("hello world");
    std::cout << hello << std::endl;

First lets make sure we have our prefix directory on the path:

export PATH=$PATH:${HOME}/local

Now we can then compile with our shinny new GCC:

g++-4.7 -c hello.cpp -std=c++11
g++-4.7 -o hello hello.o -std=c++11

Running Hello World

Running hello world is a bit trickier. We now need to tell the program loader about it and this varies from operative system to operative system.


Due to the multi-arch changes, we need to point the program loader directly to the arch specific directory:

export LD_LIBRARY_PATH=${HOME}/local/lib64

To verify that your binaries are setup correctly, use ldd:

$ ldd hello =>  (0x00007fffda7ff000) => /home/marco/local/lib64/ (0x00007f6931fa2000) => /lib/x86_64-linux-gnu/ (0x00007f6931cf8000) => /home/marco/local/lib64/ (0x00007f6931ae2000) => /lib/x86_64-linux-gnu/ (0x00007f693175b000)
    /lib64/ (0x00007f69322d1000)

Note that both the C++ run-time and the GCC's shared object were picked up from the correct location.


Apple - thinking differently as usual - doesn't use binutils. This means ld, gold, as etc are all a bit different. Darwin doesn't use ELF like every other sensible UNIX but it uses MACH-O instead - a bad nerd pun, if I ever seen one. In general this shouldn't really affect you - except you can't use familiar tools such as ldd etc.

Lets start by getting the program loader to point to our lib directory:

export DYLD_LIBRARY_PATH=${HOME}/local/lib

To verify that your binaries are setup correctly, use otool:

otool -L hello
    /Users/marco/local/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.17.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 159.1.0)
    /Users/marco/local/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)

Here you can see that the C++ run-time and the GCC dynamic library where picked up from the correct location.


On Windows the program loader path is not important, it's the main PATH variable you have to worry about3. Thus the DLLs must be on the PATH rather than on the usual variables for the program loader path. To do so:

$ export PATH=${HOME}/local/bin:${PATH}

Notice we placed our directory first in the path - this is to avoid picking up the wrong DLLs from the stock compiler. Running produces the desired output:

$ ./hello.exe
hello world

To double-check we are indeed using the correct DLLs we need to install Dependency Walker. I installed mine to C:\packages - hey, why not. You can then run:

$ c:/packages/depends.exe

And you should see something akin to this:

Dependency Walker

Dependency walker with hello world


Word of caution: notably, GCC isn't built with uninstall in mind. It doesn't support the unistall target some tarballs provide and many dicussions strongly advise against its complete manual uninstall. This is why we chose a careful location to install it, so we can simple do:

rm -rf ${HOME}/local


As you can see its really easy to build GCC from source, install it and start using it to compile C++-11 programs. In future we will cover how to compile auxiliary libraries such as boost with C++-11 support so you can use the full power of the language.


1 : I won't go in to too much detail on the finer points between MinGW and MSYS and so on; if you are interested, check the post MinGW, Cygwin and Wine.

2 I had one or two problems when compiling PPL in the past so I gave up on it, and haven't noticed significant optimisation problems yet. Of course, if this was a production compiler I certainly would compile it with PPL.

3 Or better yet, the windows loader uses only one path variable for both the executables and the shared libraries.

Date: 2012-06-08 08:43:47 BST

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Wednesday, June 06, 2012

Nerd Food: .signature

Nerd Food: .signature

Yanis Varoufakis

The problem with economics is that, at best, it can offer an interesting theory of what an economy populated by algorithms will look like. – Yanis Varoufakis

One of the few advantages of the Global Financial Crisis is that it opened a profound debate about Economics. As a software engineer, I must say I share some of the dislike for the dismal science, as it seems far removed from the Popperian principles we hold dear. However, people like Varoufakis force me to keep my mind open due to their refreshing way of looking at things. In this sentence he strikes at the heart of the greatest risk with models: one can stare at the model for so long as to confuse it with reality. This is something that, unfortunately, computer scientists are not immune to. Falsifiability should always be in the back of our minds.

Date: 2012-06-06 11:27:13 BST

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Sunday, June 03, 2012

Nerd Food: Interesting...

Nerd Food: Interesting…

Some interesting stuff I bumped into these last couple of weeks.


  • LLVM 3.1 Release Notes: Clang/LLVM 3.1 is out! To be fair I'm more GCC 4.7 these days, as the C++ 11 support is a bit more mature - but as soon as I get a chance I'll try to play around with Clang again. I got to say I was a bit underwhelmed with the amount of C++ 11 features on this release, but I guess they're not that far now.
  • Elements of Modern C++ Style: A classic overview text on C++ 11 by Sutter.
  • The C++ Pub Quiz: This would have been so useful a few weeks ago, its not even funny. Don't start a pub quiz without it.
  • C++ 2011: Great overview of C++ 11 by Dietmar Kuhl. Its a presentation - it would be great to get the video.
  • Perfect forwarding and overload resolution and C++11 range-based for loop: There's just so much new stuff with C++ 11 its hard to keep up. Boris blog is, as usual, the place to go for in-depth discussions of C++ 11 machinery. What I quite like about his posts is that he focuses on non-obvious issues of these new features, which is a great time-saver for C++ 11 newbies.
  • Monte Carlo C++ AMP: I haven't had a lot of time to look into AMP, but it seems quite interesting. This article gives a good practical starting point. Of course, being a Linux dude, OpenCL is more my kind of solution, but its always good to keep up with Microsoft.
  • The Future of C++ Concurrency and Parallelism: Some reflections by Bartosz on concurrency and C++ 11. Its good to understand what we got - in terms of the options available - and we're we are going.

Other Programming Topics

  • Highlights from the PostgreSQL 9.2 beta: LWN rocks, as usual. Its shaping up to be another amazing Postgres release. If you are a heavy cache user, you may want to have a look at the potential of HStore with JSON. Range types look interesting, and performance has improved - as usual. Random quote: "PostgreSQL now scales smoothly to 64 cores and over 350,000 queries per second, compared to topping out at 24 cores and 75,000 queries per second on PostgreSQL 9.1. Throughput is better even at low numbers of cores.".
  • LGM: GIMP's new release, new über-core, and future: More LWN rockage. I'm by no means an arty person, and I very rarely use the GIMP - yet I find its development to be extremely instructive. People don't seem to realise that GTK is an offshoot of GIMP just like GEGL. They may be slow but make no mistake, these people are geniuses. Great to see that progress is now in leaps and bounds.
  • Emacs: How to Copy/Cut Current Line: A couple of useful productivity functions by Xah Lee. A bit like dd on vi.
  • Tanenbaum’s advice for building product, networks, and living life: Although I was more of a Linus fan-boy on the Torvalds v Tanebaum, I got to say I really respect the man. Bumped into this post; its much more widely applicable than just for protocol design. Visionary, really.
  • How Google Developers Use Ubuntu: (video) Never quite realised just how big Ubuntu was at Google. To be fair, I kind of assumed they'd be using some kind of Debian - making your own distribution is just silly. But still, its good to see that they get it.
  • Writing a CV in LaTeX: I'm not really looking for work right now - having too much fun hacking at home! - but when the time comes to join the merry go round, I'll try to write my CV in LaTeX rather than LibreOffice.


  • The fourth quadrant: A map of the limits of statistics : Bumped into this old essay from Taleb. As usual very thoughtful. Its very important we don't blame the tools but instead reflect on their usage, very much like Taleb and Wilmott keep on insisting.
  • CDS and Synthetic CDOs Explained: CDS and CDO's are so key to the current financial problems that its vital to have a good understanding of their inner workings. But often they are explained in really baffling terms. Myers does a better job than most.


  • So You Want to Open Source Your Code?: I've got the utmost respect for the Kitware guys, makers of CMake, CDash et al. Not only they were really early birds in understanding how to merge FOSS and business, but they really kept at it without ever wavering. This post explains the key things to bear in mind when trying to put your internal code out in the community - and making a success of it. It distils their experience so definitely worth a read if you are thinking about this sort of thing.
  • Christian Right Lobbies To Overturn Second Law Of Thermodynamics: The onion just rocks, their parody is just so spot in its cringe-worthy.
  • A Screaming Man: Watched this on TV5. Unfortunately my French isn't great so missed a bit, but seemed like a great movie and the soundtrack was amazing. In particular, will be buying some Ballaké Sissoko stuff real soon now.

Date: 2012-06-03 19:27:19 BST

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