A collection of coding snippets, tips, hints and random thoughts.
Today I was looking for a better console font for the Apple terminal application. Up until now I was using a variant of the Terminus font, but it did not have the line drawing characters. So several programs looked quite borked. But there is a nice page with a collection of the X11 terminal fonts in Apple’s dfont format, which you know and like from all kinds of Linux distributions.
You have to tweak the spacings, for example for the 7×14 font you need to pick 0.98 and 0.93 for the horizontal and vertical spacing. Also make sure to use the fonts at their specified size. I.e. the 7×14 font at 14 points only.
I have set up my Raspberry Pi as a music and file server. My requirements were:
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.
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.
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.
XCode 4 has always been incredibly slow for me. The first release, 4.0, was especially bad. But that was just a .0 version. The next release 4.1 is much better, but it has also severe drawbacks, concerning performance. Everytime I start it, and not even do much with it, my system gets incredibly slow. That is on both a C2D 2.8 GHz MBP and also on a quad-core i7 MBP. Both machines come with 4 GB of RAM, and after firing XCode up and loading a large project, still at least 500 MB of it remains free. However, speed is abysmal. I just found the tool vmmap in OS X, and it gives me this output:
==== Summary for process 32136
ReadOnly portion of Libraries: Total=265.8M resident=114.4M(43%) swapped_out_or_unallocated=151.5M(57%)
Writable regions: Total=16.2G written=149.6M(1%) resident=360.9M(2%) swapped_out=6156K(0%) unallocated=15.9G(98%)
REGION TYPE VIRTUAL
=========== =======
CG backing stores 19.4M
CG image 268K
CG raster data 2840K
CG shared images 3472K
CoreAnimation 180K
CoreGraphics 16K
CoreImage 108K
CoreServices 1704K
IOKit 61.2M
MALLOC 337.4M see MALLOC ZONE table below
MALLOC (reserved) 15.6G reserved VM address space (unallocated)
MALLOC freed, no zone 30.5M
MALLOC guard page 64K
MALLOC metadata 128.8M
Memory tag=240 4K
Memory tag=242 12K
Memory tag=243 4K
Memory tag=249 156K
Memory tag=251 64K
OpenCL 60K
OpenGL GLSL 1372K
OpenGL GLSL (reserved) 128K reserved VM address space (unallocated)
SQLite page cache 14.6M
STACK GUARD 56.1M
Stack 19.7M
VM_ALLOCATE 16.1M
__CI_BITMAP 80K
__DATA 33.9M
__IMAGE 1256K
__LINKEDIT 59.5M
__TEXT 206.4M
__UNICODE 544K
mapped file 72.9M
shared memory 13.6M
=========== =======
TOTAL 16.7G
TOTAL, minus reserved VM space 1.1G
So the virtual memory space that XCode takes is more than 16 GB! The actual memory taken is “only” 1.1 GB, which is still huge, but my Emacs also takes 500 MB with tons of C++, Python and LaTeX buffers open.
The question is: can the unallocated, but reserved 16 GB address space degrade the performance? I have too little knowledge of the workings of virtual memory on Intel CPUs under OS X. But this value seems incredibly huge.
Update: I have asked a question on Stackoverflow, and have gotten some useful answers. What did help was removing my build/ folder from the git. Accidentally, a colleague checked in four files in the build/ folder. This made Xcode very slow, since it was checking the git status during compilation all the time. Still, Xcode 4 is much slower than Xcode 3 after this. So I also upgraded our machines to have at least 8 GB of RAM. This was definitely much of an improvement. It seems that development machines using Xcode 4 should have 8 GB RAM minimum. The more, the better…
The EFF has published a Firefox extension to force HTTPS on as many websites as possible. This is a good idea(tm). But on OS X I use Safari, not Firefox. So I was wondering if there is a similar extension for Safari. It turns out there is. However, this extension is available in source only. The reason for this is given in a blog post by the developer. In short: The Safari extension API is limited, and the extension cannot guarantee that all your session cookies are transferred via HTTPS, making you vulnerable to stuff like Firesheep. And that is a bad thing(tm). But it is still useful, since it will redirect you to secure versions of the websites. One thing to note when following the build instructions: You need to enroll in the free Safari Dev program, and get a developer certificate. This is very well described over at Apple’s developer center. After that, you can enable the developer menu in Safari’s settings and just install the extension from the cloned git repository.
