gergap's Blog

GCode Simulator

Gerhard Gappmeier — Sun, 19 Aug 2018 00:00:00 +0200

Last year I’ve built a Mendel90 3D printer. Soon I’ve printed an adapter for the Proxxon Micromot 50, so that I could use the printer also for drilling and milling. Drilling was easy, and this weak I gave milling a try and experimented with milling PCBs created with …

Types of Memory Leaks

Gerhard Gappmeier — Fri, 03 Aug 2018 00:00:00 +0200

There exists more than one type of memory leaks with different effects and different way to detect them:

The typical memory leak: a piece of memory the gets allocated but is not freed anymore. This is the classic type of memory leak, for what C and C++ gets blamed for …

Restrict SSH to rsync

Gerhard Gappmeier — Wed, 05 Jul 2017 00:00:00 +0200

Today I created limited access for a buildbot user via SSH. The build machines need SSH access to upload built software to our file server. This works using rsync over SSH.

Whereas real users are using a Yubikey and not SSH key files anymore, the build machines still require SSH …

Download Wordpress Media Library

Gerhard Gappmeier — Mon, 03 Jul 2017 00:00:00 +0200

I’m currently in the process of migrating my old Wordpress blog to Pelican. In Wordpress it is easy to export all your posts as an XML file, but this does not export the referenced images. Also there is no export-all functionality, or FTP access or something like that. Downloading …

Using virtualenv on Gentoo

Gerhard Gappmeier — Mon, 03 Jul 2017 00:00:00 +0200

When using Python you should always use your package mangager (portage on Gentoo) to install python software. Other tools like pip install would interfere with your system and can damage your local python installation.

But sometimes you need python modules which dont exist or are too old in your distribution …

Setting KVM hostname per DHCP

gergap — Fri, 17 Feb 2017 13:23:00 +0100

The Problem

One problem with virtual machines is, when you clone one you also copy the complete configuration including hostname, static IPs, etc. To fix this you need to boot the cloned VM, edit the config and reboot it. The problem is that you will have at least temporary hostname …

VS2017 has got CMake support

gergap — Tue, 24 Jan 2017 13:13:00 +0100

We are using CMake already for years in my company to develop cross-platform software. CMake is really a great piece of software, but the user experience in Visual Studio was not great. It worked, but we often needed to explain how, and the typical Visual Studio user didn’t know …

Profiling Memory using GNU glibc tools

Gerhard Gappmeier — Fri, 20 Jan 2017 00:00:00 +0100

One of the tools I’m using already quite a while to profile memory usage is the built-in profiling functionality in glibc. For some reason this isn’t known very much, so I thought documenting it here makes sense, so I can simply point the people to this post, instead …

Fix performance of VIM syntax highlighting in XML files

gergap — Mon, 12 Dec 2016 12:35:00 +0100

Normally Vim is damn fast and this is one reason why I love it. But today I got an XML file with over 3 million lines and after opening that file I wanted to jump to the end of the file. This took me over 1 minute which is unacceptable …

Easily debug unit tests with GDB

gergap — Fri, 28 Oct 2016 20:57:00 +0200

A while ago I developed an ANSI C based unittest framework that gives me the same comfort as the Qt’s unit test framework in C++, but small and portable for embedded ANSI C applications.

You can find the framework here on github: http://gergap.github.io/unittest

This framework …

Latency Heatmaps

gergap — Fri, 28 Oct 2016 13:55:00 +0200

Latency heatmaps are a great way to visualize latencies which are hard to grasp from pure test data. Brendan Gregg (http://brendangregg.com) has written a great Perl script for generating such heatmaps as interactive SVG graphics. Also the flamegraphs are just awesome, but this is another story.

(Unfortunately SVGs …

Using Let’s encrypt for non-web servers

gergap — Wed, 07 Sep 2016 15:16:00 +0200

I think I don’t need to explain Let’s encrypt anymore. But what many people are struggling with is to use Let’s encrypt certificates for other services like SMTP, IMAP, IRC, etc.

Using certbot this is quiet easy (See https://certbot.eff.org for installation instructions).

When certbot …

Building MinGW Cross-Compilation Toolchain using CrossDev

gergap — Mon, 07 Sep 2015 08:02:00 +0200

This is mainly a note to myself. Maybe it’s useful for you too.

Actually building cross-compiler toolchains using crossdev is easy, but there are some pitfalls.

Remove any compiler environment variables before building, or the build will fail
For building MinGW toolchains the openmp useflag must not be set …

Another Update of my #Vim wombat256 colorscheme

gergap — Thu, 20 Aug 2015 22:50:00 +0200

Just updated my #Vim config and wombat256 colorscheme to show a nice
color column area with a decent non-distracting background color.

This is how it looks like (click to enlarge):

Wombat256 for #Vim has now an own Git Repo

gergap — Thu, 20 Aug 2015 18:35:00 +0200

I just moved my wombat256 colorscheme for console #Vim to a separate Git repository. This makes it easier for you guys to use it simply by using pathogen & Co. I also updated my Vim repo to make use of this separate repo.

Checkout it out on https://github.com/gergap …

Vim Section Navigation

gergap — Thu, 20 Aug 2015 13:07:00 +0200

Normally #Vim uses easy to remember mnemonics like d2w (delete two words).
But when it comes to section navigation using ‘[[‘, ‘]]‘, ‘[]‘, and ‘][‘ it looks weired.
At least if you expect, that the opening and closing brackets are somehow matching opening
and closing braces.

(In C like languages function scopes {…} are sections …

Updated Wombat256 Colorscheme

gergap — Wed, 19 Aug 2015 07:54:00 +0200

After working a while with the Solarized colorscheme I came back to my wombat256 colorscheme, which is based on the original wombat for gvim from Lars H. Nielsen. Yesterday I improved it a little bit to fix some issues that I didn’t like:

Fix background color of NonText
Add …

CMake uninstall

gergap — Tue, 18 Aug 2015 08:44:00 +0200

CMake is a great tool when building cross-plattform software. It offers also install target so you can build and install software this way:

# create of-of-source build directory
mkdir bld
cd bld
# run CMake to generate a Makefile
ccmake ..
# Build in 4 cores
make -j 4
# Install into CMAKE_INSTALL_PREFIX (default is …

YCM FixIt Feature

gergap — Tue, 11 Aug 2015 15:59:00 +0200

YouCompleteMe (YCM) is really an awsome plugin. But today this blog post is not about completion support, it’s about YCM’s FixIt feature. If you are developer and have seen already compiler errors like this:

expected ';' at end of declaration

then I’m sure you also thought already: “If …

New Keystroke GUI with Vim support

gergap — Tue, 11 Aug 2015 14:37:00 +0200

I’ve created an updated version of my Keystroke-gui keylogger, which can be controlled by Vim Hooks. Keystroke is keylogger and visualizer which can be used for screencasts. This is especially useful when recording screencasts for Vim, because in Vim’s normal mode you cannot see what is typed, opposed …

Mk script is now on github

gergap — Sat, 08 Aug 2015 11:12:00 +0200

An updated version of my mk script is now available on github. This way it is easier to update it. See https://github.com/gergap/mk

I blogged about it before in 2014, see http://gergap.de/mk-script-to-simplify-out-of-source-builds.html

Fixed redraw issue in vim-konsole

gergap — Fri, 31 Jul 2015 17:07:00 +0200

A while ago I’ve written the little vim-konsole plugin which makes Damian Conway’s vim-autoswap working with KDE’s Konsole application.

This caused some redraw issues in Vim when switching buffers, whichs is very annoying. I needed to press C-L to force a redraw everytime this issue occured.

I …

Using the system clipboard in Vim over an SSH session

gergap — Fri, 31 Jul 2015 09:31:00 +0200

One of the advantages of console Vim is, that you can use it in a console SSH session. This way you can work on a remote machine also on slow connections and don’t need laggy remote desktop software. This is even more important if the remote machine is a …

Vim Cheat Sheet

gergap — Wed, 17 Dec 2014 09:24:00 +0100

Hi guys,

I just made my personal Vim Cheat Sheet available using Dropbox.

https://www.dropbox.com/s/q6ka12yiag6lc66/vim-cheatsheet.md?dl=0

Vim really rocks. Often people don’t believe that an editor that looks so “old school” can be effective. It’s really hard to explain. The best …

ESA is using CDE?

gergap — Sun, 16 Nov 2014 18:02:00 +0100

Hi,

in the last days I was constantly watching the news regarding the ESA mission Rosetta. Wasn’t this impressing? Landing on a comet so far away?

Anyway, when looking at the various images on the ESA website I’ve seen some screens which were running this CDE style software …

The good old µA741

gergap — Fri, 12 Sep 2014 08:02:00 +0200

A cool gadget for everybody who want to see the good old µA741 in action. The XL741, a discrete version of µA741: http://www.elektor.de/news/XL741/

Der gute alte µA741 OPV

gergap — Fri, 12 Sep 2014 08:02:00 +0200

Für alle die sentimental werden beim Anblick eines µA741 gibt es den jetzt diskret aufgebaut: http://www.elektor.de/news/XL741/

Base64 decoding inside Vim

gergap — Tue, 26 Aug 2014 20:09:00 +0200

Today I needed to decode a part of Base64 data which was embedded in an XML file. Normally I would store this fragment in an own file and use the base64 commandline tool for decoding. But today, due to my recent Vim activities, I was asking myself if I could …

Why Vim?

gergap — Fri, 22 Aug 2014 14:13:00 +0200

It would be reason enough that Vim is so powerful. With a few keystrokes you can achieve results where with GUI editors you need a lot of click and point and repetitive tasks which you can simply automate with Vim. With Vim I can leave my hands on the home …

mk script to simplify out-of-source builds

gergap — Tue, 04 Mar 2014 15:55:00 +0100

Almost all projects that I’m working on are using CMake today with out-of-source builds, which means it doesn’t pollute your source directory with generated files. Normally this means I create “bld” folder on the top-level project directory and run CMake to generate the Makefile like this:

cd /path …

My first Qt contribution

gergap — Wed, 03 Apr 2013 08:51:00 +0200

I’m proud to announce that my first contribution to Qt made it into Qt5.1. It is also mentioned on the “New Features in Qt 5.1” Wiki entry:

“moc: New keyword in Q_PROPERTY: MEMBER let you bind a property to a class member without requiring to have a …