Category: Watching

Deploying Qt based applications without the hassle.

With the advent of the Qt Installer FrameWork (QtIFW), it has never been easier to provide installers for your Qt based applications. Such installers can be either online (i.e. they fetch contents from the internet from repositories during the installation process, thus allowing updates), or offline (i.e. all the contents is bundled into the installer). …

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Run a GL application on the Nef cluster with virtualGL

The nef cluster comes with 6 nodes equipped with Nvidia GPUs. Typically, they are used with cuda or opencl to run some highly parallel computations. But you may also run OpenGL applications on them.

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Trick of the day: monitoring the Linux filesystem changes in “real time”

Ever wanted to monitor the filesystem changes ? Since Linux 2.6.25, the kernel provides us with a signal driven I/O notification API and the inotify-tools RPM provides a set of tools to interact with the kernel. inotify in action: a simple way to test this API is to run the following command in a terminal …

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Trick of the day: prefetching a callback into the QApplication event loop

Qt provide a standard mechanism (aboutToQuit() signal) to insure that a callback is executed at the end of the QApplication event loop. This is typically used to add some cleanup code to your application. Infortunately, Qt does not provide a “aboutToRun()” if you want to execute an initializing code just before the event loop. Nevertheless …

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The LD_PRELOAD trick

If you ever wanted to replace some symbol in a library, in order to inspect what happens in a binary you don’t have the source code or even to inject some code, this can be done using the LD_PRELOAD trick. To use it, invoke your binary as such: $ LD_PRELOAD=somelib.so executable.

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Speech recognition using PocketSphinx

CMUSphinx, where CMU stands for Carnegie Mellon University, is an open source toolkit for speech recognition. This proof of concept, aims at using speech instead of a mouse to trigger transitions within a state machine, and have a visual feedback of it.

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