As you may know, developing for multiple platforms is one of my strengths. Strictly speaking, it’s a basic requirement if you are involved in such a product like VirtualBox, which runs on every major (and several minor) platform available today. Beside the GUI, which uses Qt and therewith is portable without any additional cost (which isn’t fully true if you want real native look and feel on every platform, especially on Mac OS X), all the rest of VirtualBox is written in a portable way. This is done by using only C/C++ and Assembler when necessary. Everything which needs a different approach, because of the design of the OS (and the API’s which are available there), is implemented in a platform dependent way. In the history of VirtualBox, several modules are created and grown by the time, which makes it really easy to deal with this differences. For stuff like file handling, paths, strings, semaphores or any other basic functionality, you can just use the modules which are available. On the other side it might be necessary, for a new feature we implement, to write it from the ground. In the following post I will show how to create a file shortcut for the three major operation systems available today.
Have you ever wondered how Mac OS X knows which file type belongs to which application? On Windows there is the registry. An installer writes the necessary info into it. Most applications on Mac OS X doesn’t come with an installer, they are just moved from the downloaded DMG file to the
/Applications folder. So a developer doesn’t have the ability to take action when the user “install” the application. Anyway there is no need to provide an installer for just this task, cause Mac OS X register file type associations on the first start of the application. In the following post, I will show how to do this, but furthermore I will show where this information is stored and how it could be reseted.