SGrottel.de

Updating WordPress is kind of pain. I can completely understand why many people do never update their (non-personal) sites. This is not a large WordPress installation. One site, roughly half a dozen plugins, one theme, and that is it. Nevertheless, today I made the effort to back up the data base and files and to update everything. Two plugins failed to work properly afterwards and it took me two hours to fix everything. However, don’t get me wrong. The heaviest problems I got did not originate from one of the plugins itself, but from the way I used it. Meaning, it was my own fault. Still, a pain.

I wrote this letter in German only.

o.T. … too tired … next week …

Life is not easy as a multi-platform developer. This was the main reason for projects like VISlib and the now dead and buried TheLib. But times have changed. The new C++11 standard brought in some very nice and useful classes. Maybe the only thing I really miss right now is IPC, RPC and fundamentally sockets. However, the new threading classes are very nice, like, of course, std::thread.

Well, I am a Windows-software developer. And I continuously port my code to the other platforms, like Linux and sometimes OS X. Thus, there are always some issues when doing something for the first time. For example, when I tried to build my first test program for std::thread unter Ubuntu, I got the std::exception:

Operation not permitted

Well, of course, I linked against pthread. But something must have gone wrong. I asked the almighty Internet, and of course StackOverflow answered: http://stackoverflow.com/questions/9945391/stdthread-creation-throws-exception

In short words: It was an issue of the ordering of the arguments to Gcc, which in my opinion is one of the most annoying issues with the Gcc.

This does not work:

g++ -std=c++0x -lpthread -o test ./test.cpp

This does work:

g++ -std=c++0x -o test ./test.cpp -lpthread

User user405725 nicely summarized it in his comment:

You generally have to specify libraries AFTER object files or they are not pulled in.

Ok. So what about CMake: StackOverflow: http://stackoverflow.com/questions/1620918/cmake-and-libpthread

The different possibilities may also result in different parameter ordering. Following the formal way and using find_package:

cmake_minimum_required (VERSION 2.6)
find_package (Threads)
add_executable (myapp main.cpp ...)
target_link_libraries (myapp ${CMAKE_THREAD_LIBS_INIT})

everything works like it should be.

However, if I try to take the short way out, e.i. by specifying the arguments directly, like:

SET(CMAKE_CXX_FLAGS_DEBUG "... -lpthread")
SET(CMAKE_CXX_FLAGS_RELEASE "... -lpthread")

on my Ubuntu installation with my Gcc I ended up with the wrong ordering of arguments and my test program failed.

I like Cmake. I works. But you should not try to enforce your way of doing things if it is against the way of CMake used to do things. It will work up to some degree, but you will get problems going beyond that point. Just follow the way of CMake and, most of the time, everything will work.

I wish all of you a merry and restorative time of Christmas. Take a deep breath and calm down.

I am back in Dresden. This was by far the most exhausting business travel ever. The Siggraph Asia 2014 was quite alright, but it completely filled up the days in the Chinese time zone. An the work for the German time zone in this week was as submission to the EuroVis 2015, the writing of a funding proposal, of a final project report, and the reading and commenting of a Ph.D. thesis of a friend of mine. There was few time left for sleeping and none at all for anything else. And that fun lasted the full seven days. My flights back to Germany were today, Sunday. From 4 am. Shenzhen time until now 8 pm. German time. And tomorrow morning I will be giving a lecture. I am so looking forward too that.