Tag Archives: Gnome

A tale of three build systems


While we’re still 30s behind hand-written make, I totally would use any of the two over hand-written Makefiles.

As you might have noticed, meson is the new kid on the block. Step by step I am currently converting some projects to it, spearheading Shotwell. Since Shotwell only “recently” became an autotools project, you may ask why. Shotwell had a hand-written makefile system. This made some tasks that would have been incredibly easy with autotools, such as mallard documentation handling, more complicated than it should be. Since autotools provides all the nice features that you want for your GNOME environment, it made sense to leverage that.

Number games

Here are some numbers from the various transition phases. All taken on my i5 X201 laptop.


  • We build from a fresh git checkout (or git clean -dxf)
  • All builds are generated on the same machine with make -j $(($(nproc) + 2))
  • In the case of Meson, the ccache cache was emptied before

Shotwell 0.22

real	0m0,011s
user	0m0,004s
sys	0m0,004s

real	5m15,892s
user	17m30,392s
sys	1m10,984s

Shotwell 0.23.0

Shotwell’s makefile had a subtle rule issue that caused the plugins to be compiled several times over with valac. Also it was calling pkg-config with each compiler call, so after fixing that, we get these numbers for the compile step:

real	2m1,760s
user	6m31,788s
sys	0m26,788s

Shotwell master


autogen.sh (including configure run):

real	0m32,315s
user	0m26,900s
sys	0m0,984s


real	2m25,164s
user	7m47,380s
sys	0m29,028s


mkdir build && meson build

real	0m1,529s
user	0m1,056s
sys	0m0,304s

ninja -C build

real	2m9,369s
user	7m17,276s
sys	0m33,660s


The time of the year…

Springtime is releasetime!

Monday saw a couple of new releases:


Shotwell 0.26.0 “Aachen” was released. No “grand” new features, more slashing of papercuts and internal reworks. I removed a big chunk of deprecated functions from it, with more to come for 0.28 on our way to GTK+4 and laid the groundworks for better integration into desktop online account systems such as UOA and GOA.

GExiv2 also received a bugfix release with its main highlight of proper documentation generation.


In Rygel, things are more quiet. Version 0.34.0 moved some helpful classes for configuration handling to librygel-core and a couple of bugs were fixed. GSSDP and GUPnP also saw a small bugfix release.



First, a wrap-up of the last Quiztime. For an excellent explanation of the issue, read this comment. Also note that this is not the most nice way to do plugins with C++, it’s a boiled down piece of code I debugged.


I’m not sure if there is some confusion about the current development model of Shotwell. I noticed that some distributions seem to try to pick up the current development branch (0.25.x). I strongly advise against that at this point in time. It has just seen a major change in the Menu handling code and might still have severe usability regressions.

While I appreciate any testing of the code, I would really not have the current unstable version of Shotwell stuck in a released distribution. If you want to try those releases on Ubuntu, there is an unstable PPA available.

So to sum up: Shotwell follows the “traditional” version scheme of “Odd is unstable, even is stable” and roughly tries to stick to the GNOME release schedule.

Quiztime II

So, following up from the last quiztime which was about the importance of explicit linking, another case from the wonderful world of shared libraries.

This time we study the implications of dlopen, its parameters and C++. Consider the program and module below. If you run that, it will crash somewhat obscurely in libstdc++. Why?

#0  0x00007f687b2eb126 in std::ostream::sentry::sentry(std::ostream&) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#1  0x00007f687b2eb889 in std::basic_ostream >& std::__ostream_insert >(std::basic_ostream >&, char const*, long) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#2  0x00007f687b2ebd57 in std::basic_ostream >& std::operator< <  >(std::basic_ostream >&, char const*) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00007f687a6f01a0 in Impl::print (this=0x558a9bc1f2e0, str="Hello") at module.cc:24
#4  0x0000558a99de3d1b in main (argc=1, argv=0x7ffca28cf538) at main.cc:31
#include <string>
class IInterface {
        virtual ~IInterface() {};
        virtual void print(const std::string& str) = 0;
#endif // INTERFACE_H
#include "interface.h"
#include <iostream>
class Impl : public IInterface {
        virtual ~Impl();
        void print(const std::string& str);
extern "C" {
void *entry_point(void)
    return new Impl;
Impl::Impl() {};
Impl::~Impl() {};
void Impl::print(const std::string& str)
    std::cerr < <"Some text to print\n";
    std::cerr << "Got passed this: " << str << "\n";
    std::cerr << "=====\n";
#include <dlfcn .h>
#include <iostream>
#include "interface.h"
extern "C" {
typedef void *(*EntryFunction)(void);
int main(int argc, char *argv[])
    IInterface *iface;
    EntryFunction f;
    void *lib = dlopen("./module.so", RTLD_NOW | RTLD_DEEPBIND);
    if (lib == nullptr) {
        std::cerr < < dlerror () << "\n";
        return 1;
    f = (EntryFunction) dlsym (lib, "entry_point");
    if (f == nullptr) {
        std::cerr << dlerror () << "\n";
        return 1;
    iface = reinterpret_cast<IInterface *>(f());
    while (true) {
        iface->print ("Hello");
.PHONY: all clean
all: main module.so
	rm -f main
	rm -f module.so
main: main.cc
	g++ -g -o $@ $< -ldl
module.so: module.cc
	g++ -g -o $@ -shared $< -fPIC

Shotwell moving along

I have released 0.25.0 on Monday.

Contrast Tool

contrast-toolA new feature that was included is a contrast slider in the enhancement tool, moving on with integrating patches hanging around on Bugzilla for quite some time.

SSL certificate handlingcertificate-warning

A second enhancement that was introduced is the option to override invalid SSL certificates. This is currenly only available in the Piwigo publisher and might be added to Gallery3 in future, i.e. all services that might be self-hosted on self-signed cerfificates.


Enhanced ACDSEE support

0.25 introduces the support of reading ACDSEE’s proprietary image tags such as titles, categories and hierarchical tags!

If you want to try it, there’s a new, unstable, PPA for Shotwell at https://launchpad.net/~yg-jensge/+archive/ubuntu/shotwell-unstable



Say you have a shared library with versioned symbols that has the function init(int *param) defined in two versions, where new_init is made the default for init (that’s what the  @@ means):

#include "shared1.h"
void new_init (int *param)
    *param = 0;
void old_init (int *param)
    *param = -1;
__asm__(".symver new_init,init@@VERS_2");
__asm__(".symver old_init,init@VERS_1");

Say you have a second shared library that provides a function do_something() uses that init from the first shared library:

#include "shared1.h"
int do_something ()
    int var;
    init (&var);
    return var;

And you have an app that just prints the result:

#include "shared2.h"
#include <stdio .h>
int main(int argc, char *argv[])
    printf ("Result: %d\n", do_something ());
    return 0;

And all of this is cobbled together with the following Makefile:

all: app
libshared.so: shared1.c shared1.h
    cc -o $@ $< -shared -fPIC -Wl,--version-script=version.script
libmoreshared.so: libshared.so shared2.c
    cc -o $@ shared2.c -shared -fPIC
app: libmoreshared.so app.c
    cc -o $@ -L. app.c -lmoreshared -lshared

What’s the output of


Update: Try to answer it without compiling and running it at first.
Update2: I forgot the version.script, sorry.

VERS_1 {
VERS_2 {
} VERS_1;

More updates

SystemD conf 2016

I will be giving a presentation at this year’s systemd conf in Berlin. If you ever wondered what the hell I am doing during the day, there’s your chance to get a glimpse 🙂

GUPnP going 1.0!

Parts of GUPnP (that is its core, GSSDP and GUPnP itself) will see a 1.0 release together with the next GNOME release. They are quite stable API-wise and functionality-wise now and I think it’s time to give them a proper blessing for that.

After that, master will become more unstable in regards of API, as there are some long-standing bugs and fixes that need an API change as well as new features to be added, such as proper IPv6 support, support for more recent versions of the UPnP standard (UDA 1.1, UDA 2.0), a more GIO-like async API,…


We’ve been digging up some annoying age-old bugs or regressions deep down in Rygel for some corner-cases (Did you know that renderer unmute was broken since 2013?)


Some more usability fixes on their way, but the big roadblock of RAW import performance is still proving to be quite annoying. Bit like a hydra, really. You cut of one RAW developer, three new seem to disappear.

Project Lazarus: GtkTerm

I took GtkTerm and poked a bit at its source, mainly for two reasons

  • Dry-run some GTK modernisation that will be necessary in Shotwell as well (GAction etc.)
  • It’s the least worst (sic) of the graphical serial terminals I tried. At least it seems to cope way better with odd USB <-> Serial adapters than t rest of the bunch
  • I use it

Ok, that’s three reasons.

If you want to have a look, head over to its repository at https://github.com/phako/gtkterm


  • Rygel is currently mainly receiving maintenance things because reason. This is hopefully changing soonish
  • I picked up Shotwell as maintainer and things are coming along nicely, though its architecture sometimes makes changes that sound really easy very hard (e.g. certain import performance improvements). Most annoying part, though, is that the merging of the awesome map feature is somewhat affected by the recent woes regarding MapQuest’s tile server
  • I’m going to be at GUADEC during its core days

That’s all for now.

Things ‘n’ stuff

Long time no blog. Sorry about that. Things have gotten a bit busy since I changed jobs in Nov 2013, moving along to the crazy and sometimes insane world of automotive in general and IVI in special. Due to that and a rather unpleasant commute, things in Rygel land have gotten a tad more silent then I hoped, not revolutionary, maybe not even evolutionary. For example, there’s still no ACL support as I promised way back on GNOME.Asia 2013.

I will have to skip FOSDEM this year for several reasons, sorry about that.

For Rygel, I hope to finish the integration of (most of) Cablelab’s changes for their CVP-2 work as they will allow nice and long requested features such as pre-transcoding or transcode caching, server-side trickmodes, simple device-dependent resource reorder (for devices that are too stupid to pick the proper resource). Unfortunately I have found a rather large feature regression with upload that seems to turn out to be somewhat nasty to fix.

That’s all for now.