I would call this post: “In a realm of all things cool Cappucino starts to rule”. I’ve noticed the framework a while ago but never quite had the time to sit down and start writing the “Hello World”. In my (graphics developer) vernacular that would be an animated ‘dot’ running around in circles. Here it goes… a bit slow, but does the job. I imagine it easy enough to improve the speed the animation by layer-backing the ‘dot’. Enjoy..
A subtlety of object identity in Obj-C
2010
02.26
02.26
A problem: given an object a of class A that aggregates a publicly accessible instance of class B determine if an instance changed by polling periodically. This comes up often in concurrent systems where an object change warrants a response while KVO is undesirable. The first thought that comes to mind is to a cache the instance of B during each cycle of polling after the comparison of the cached instance to the present value.
Our code might look like this
if (cachedB != [a valueOfB]) { triggerEvent(...); }
cachedB = [a valueOfB];
cachedB = [a valueOfB];
Unfortunately this fails miserable due to the fact that a newly allocated instance of B may occupy the same memory location as the previous one (assuming, of course, that we never retain the cached value). This is a low probability failure and is extremely hard to debug. This bug is solved by storing a timestamp upon change of instance of B inside a, and cacheing it instead of the memory address.
Joy
2010
02.24
02.24
Authentic joy is everlasting
A thing that freely permeates
As born in hearts of lovers lusting
So nascent is when we create
It hides itself in child’s smile
In ray-ing clouds of sunrise
It so resides in every shining
Of every memorable time
@rpath
2010
02.09
02.09
Leopard and (Sno) have a new way of specifying deployment location of a dynamic lib. Follow this link for an in depth explanation.
Command line is your friend :)
2010
02.09
02.09
A nifty command python -m SimpleHTTPServer will start serving the current directory on port 8000. Seems like a cute alternative to broken iChat transfers… found it here among other cute Linux miscellanea.
When in doubt about missing symbols during linking nm <filename> can be an invaluable asset. When struggling with questions about architectures of a binary otool -vf <filename> is the there to help.
Examining view hierarchy at runtime
2009
09.01
09.01
If ever in need to examine a view hierarchy at runtime HTViewHierarchy is your friend. It is a superb reverse engineering tool. F-Script can be used to this end to a degree, but sometimes one just needs a hierarchy browser.
Modifying dynamic linker paths
2009
05.20
05.20
There times when standard locations for libraries and frameworks just don’t cut it. For such times a lineup of environment variables can be used to guide the linker. Typing
man dyld
in the terminal tells the story. Also
otool -L <executable-name>
lists library locations for a given executable.
Building CGAL 3.3.1 on (10.5) Leopard
2009
04.29
04.29
Not an exercise for the faint of heart. In fact this applies to using it in your programs as well. While I managed to build the libs, I never managed to build the demos that rely on Qt.
sudo port install boost
sudo port install GMP
sudo port install MPFR
sudo port install qt3-mac
sudo port install GMP
sudo port install MPFR
sudo port install qt3-mac
sudo port install qt4-mac-devel
/opt/local/lib and type
cp libboost_program_options-mt.a libboost_program_options.a
./instal_cgal -i to enter interactive mode of their installer/opt/local/include and /opt/local/lib)export CGAL_MAKEFILE=<path_to_CGAL-3.3.1>/make/makefile_i386_Darwin-9.6_g++-4.0.1
Backported LogKit to Tiger
2009
04.13
04.13
Backporting LogKit to Tiger proved to be a pain in the neck. Crossdevelopment is tedious and the macros-riddled code looks ugly. On the upside I fixed a few bugs and reorganized the projects. The current release SymbicLogKit 0.92 is tested under both Tiger (10.4.11) and Leopard and includes source for both the framework and examples.
To include SymbicLogKit in your own projects follow these steps:
- Add SymbicLogKit as a dependent project to your project.
- SymbicLogKit is built as a private framework so you will need to add a “Copy” stage to your target to place SymbicLogKit into a Frameworks subdirectory of your build product.
- Make your target dependent on the principal target of SymbicLogKit project.
- Now we need to tell the compiler where to look for the SymbicLogKit.framework since it isn’t available for inclusion in the project (it doesn’t exist yet). Modify Framework Search Paths setting in your build settings per configuration to point to the appropriate directory relative, for instance, to your project location e.g. $(PROJECT_DIR)/../SymbicLogKit/build/Release.
- Since the framework isn’t available for inclusion in our host project we will be weak-linking to it. Locate Other Linker Flags in you build settings and set it or augment it to include -weak_framework SymbicLogKit -framework SymbicLogKit
- You may want to uncheck Build Active Architecture Only build setting.
A cute way to log in as root
2009
04.07
04.07
In Leopard one can obtain the a terminal without enabling the root account. Just type “sudo su” and provide your user password. Seems like a cleaner way to operate as root.