Install cmake 3.11.1 on Ubuntu
Sometimes you just want a newer version than ubuntu ships. This code will update cmake to version 3.11.1 or any other version you want.
Continue readingAutomatic VirtualBox module signing for UEFI
These steps are for all those people who hate to sign the Virtualbox modules every time and don’t want to disable UEFI.
Continue readingUbuntu: automatic password for second encrypted disk
I just encountered the problem that I have to type two passwords at startup, for two encrypted disks. My first disk is encrypted through the Ubuntu installer. After some searching I found the perfect solution for that task. In german, it’s called “Schlüsselableitung”, in English derived keys. But perfect solutions often have a big issue why they don’t work, like here. I’m using Ubuntu 16.04 which uses ´systemd´, and that has problems with derived keys. So I found the second most perfect solution for me, using a key-file. Some people argue that this is a security issue, but the derived key is also obtainable with root rights, just like a key-file. And by the way, your private keys of your certificates are also stored on that disks and nearly nobody complains about that.
Continue readingQt Signals & Slots: How they work
The one thing that confuses the most people in the beginning is the
Signal & Slot mechanism of Qt. But it’s actually not that difficult to
understand. In general Signals & Slots are used to loosely connect
classes. Illustrated by the keyword emit, Signals are used to
broadcast a message to all connected Slots. If no Slots are connected,
the message “is lost in the wild”. So a connection between Signals &
Slots is like a TCP/IP connection with a few exceptions, but this
metaphor will help you to get the principle. A Signal is an outgoing
port and a Slot is an input only port and a Signal can be connected to
multiple Slots.
Should I use Qt containers or the std ones?
If you come from plain vanilla C++, you only know the C++ Standard
Library with its containers like std::vector. If you know how to use
them, you can accomplish your tasks pretty fast. But if you’re coming
from another language, the naming might be a bit odd. The Qt containers
offer both, C++ style and Java style naming of methods. So coming from
another language the Qt one’s might be easier to use.