Author: root42

What about C++11 in Xcode?

This started out as a very small problem: I am using C++, Objective C++ and Objective C mixed in one project. This usually works pretty well. However, when including MapKit, the compiler choked on an Objective C++ file. It seems the MapKit.h header wants to use isinf(). This function has been introduced with ISO C 99, but it it is not included in ISO C++ 98. Hence the failure of Xcode’s gcc and clang compilers.

To work around this problem I was thinking of trying to set the project settings to use ISO C++ 11, or C++ 0x, since Xcode’s compilers are not that up to date. This is pretty easy:

And I guess this would work for most people. However, I am also using boost in this project. And I guess it is rather up to date, concerning the new language specification. However this also means that there is a problem with clang’s support of the language. I get a ton of errors in boost when switching to C++ 0x in clang:

In short, I think the C++ 11 support is not quite there yet with Xcode 4.2 and clang 3.0. I will try to post updates when future Xcode releases are coming out. If, alternatively, someone has hints on how to compile boost with clang 3.0, I am also glad to try that out.

Update: There is a fork on gitorious of the boost on iPhone build script, which already uses the clang compiler. I hacked the script even more to use –std=c++0x as a flag and it builds fine. Now I will try to link this new framework to an iOS project compiled with clang using C++ 0x.

Update 2: I found the root of the problem. The fantastic people over at #boost on freenode helped me figuring it out. In short: boost::fusion defines nil, which is an Objective C keyword. Thus we get lots of problems. Objective C defines nil and Nil in objc/objc.h. A minimal program that compiles successfully:

#include <boost/phoenix/core/reference.hpp>
#import <CoreFoundation/CoreFoundation.h>

int main()
{
    return 1;
}

Using this command line: 

/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/clang++ 
-isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk 
-framework Foundation -Fpath/to/boost/framework --std=c++0x -arch armv7 
-stdlib=libc++ -mthumb -miphoneos-version-min=5.0 foo.mm -o foo

If you swap the to include / import statements, the program will not compile, since now the ObjC nil makes boost break. There is a boost ticket tracking this issue, with a proposed patch attached, which renames the boost nil to nil_.

Update 3: The patch works fine, but now I get internal compiler errors from clang. The compile triggers a segmentation violation at some point during the compilation of my project. I guess clang 3.0 is still a bit experimental. I submitted a bug report and will revert to using the default settings of Xcode for the time being.

Using gpsbabel and a USB to serial adapter on OS X to read out a Garmin GPS

For a couple of years I have been owning a Garmin eTrex GPS receiver. It’s a nice little tool, pretty ruggedized and reliable. I use it to track for example hiking tracks and also sometimes for Geocaching. It has a serial interface for downloading the data. However, my MacBook Pro does not have a serial port. So I bought one of the ubiquitous Digitus USB to Serial adapters. With this and gpsbabel (sudo port install gpsbabel, if you have MacPorts), it is really easy to download the track data for example to a KML file to be viewed in Google Earth:

gpsbabel -t -i garmin -f /dev/cu.usbserial-XXXXXX -o kml -F mytracks.kml

The XXXXXX in the device filename varies from device to device, you probably can also use /dev/cu.usbserial-* as the device filename, if you have only one of these things attached to your computer. It is important not to use the tty device file, since it seems not to work. I do not know yet what the exact difference is, but I will come back when I found out.

BibTeX bibliography title

The other day I was using the moderncv document class to create a CV. I also added my publications to the CV, which was supposed to be in German. BibTeX created a section “Literatur” for this. Obviously, I wanted the title of the bibliography to be “Publikationen” instead. When using the german package of babel, you can change the bibliography title like this in the LaTeX preamble: 

addtocaptionsgerman{renewcommand{refname}{Publikationen}}

Clementine Player

A couple of years back, I was a big fan of Amarok, the music player. Then came along a rewrite and version 2.0, and I also switched to OS X. The version 2.0 was not very nice, stable or useful. The OS X version was very hard to install, due to the KDE dependencies. So I ditched Amarok. I replaced it with CogX for a while, and now I am using the horrid iTunes and the wonderful mpd (together with MPoD and Theremin). But today I read about the Clementine Player. It’s a cross platform Amarok 1.4 fork. And after 10 minutes of testing, I think it’s wonderful!

Where to put a label on a LaTeX figure

I just found out that LaTeX is sensitive as to where you put the label command in a figure environment. For example if you do something like this:

begin{figure}
  centering
  includegraphics[width=0.95columnwidth]{sompic}
  label{fig:some-pic}
  caption{Some caption.}
end{figure}

if you now do a ref{fig:some-pic}, the reference will point to the parent element of the figure environment. For me, I got a reference to the subsection enclosing the figure. This was very irritating, because the text then said “see Figure 3.4.2.4 for details.”
Instead you need to place the label in or after the caption command. For some reason the ref will then point to the figure: 

begin{figure}
  centering
  includegraphics[width=0.95columnwidth]{sompic}
  caption{Some caption.}
  label{fig:some-pic}
end{figure}

Update: And here is also the answer to the question why it is necessary to do it this way.

Another OS X git UI: SourceTree

Besides gitx, I now was shown another git user interface for OS X. It is called SourceTree:

It is more mature and feature-rich, compared to gitx. But it is closed source. However, it is free (as in beer) for the time being in the App Store. So far, the program seems really nice. Let’s see how long I will continue using it, and if I’ll go back to gitx at some point.