[SOLVED] Difficulties installing a C++ library properly

crazy-yiuf · 07-14-2016, 11:13 PM

I'm trying to install a development library called nanogui-sdl:
https://github.com/dalerank/nanogui-sdl
It is not available as a debian package, as far as I know. Here's what I'm trying so far:

Code:

cd /usr/local/lib
git clone --recursive https://github.com/dalerank/nanogui-sdl
cd nanogui-sdl
cmake ./
make
cd ..
ln -s nanogui-sdl/libnanogui.so libnanogui.so
ldconfig

It's "installed", so I'm going to try to compile the example that comes with the package. I'll note that the example is included as a cmake target, and there is a binary in /usr/local/lib/nanogui-sdl which runs beautifully. Like, really beautifully. Worth checking out if you ever use SDL.

Code:

cd ~/src
g++ example2.cpp -llibnanogui.so -I/usr/local/lib/nanogui-sdl

In file included from /usr/local/lib/nanogui-sdl/include/object.h:15:0,
                 from /usr/local/lib/nanogui-sdl/include/widget.h:15,
                 from /usr/local/lib/nanogui-sdl/include/screen.h:17,
                 from example2.cpp:14:
/usr/local/lib/nanogui-sdl/include/common.h:15:22: fatal error: Eigen/Core: No such file or directory
compilation terminated.

I'm guessing that I'm doing something totally wrong. I'm not used to cmake, or installing this sort of library without dpkg in general.

crazy-yiuf · 07-14-2016, 11:46 PM

deleted post

crazy-yiuf · 07-15-2016, 12:08 AM

Edit: Now I'm getting it to compile with:
g++ example2.cpp -std=gnu++11 `sdl-config --cflags` -lSDL2 -lnanogui -I/usr/local/lib/nanogui-sdl -I/usr/include/eigen3

But ldd ./a.out gives:
...
libnanogui.so => not found
...

I'll try it again in the morning.

NevemTeve · 07-15-2016, 02:23 AM

Try 'make install'

Code:

make
make install
ldconfig

Note: /usr/local/src would be more plausible location for the source.

knudfl · 07-15-2016, 07:20 AM

Quote:

fatal error: Eigen/Core: No such file or directory

# apt-get install libeigen3-dev

... provides /usr/include/eigen3/Eigen/Core : the file Core is a C header.

Either point to Eigen, like CFLAGS=-I/usr/include/eigen3/Eigen
or symlink Eigen to e.g. /usr/local/include/ :
# cd /usr/local/include/ && ln -s /usr/include/eigen3/Eigen

-

crazy-yiuf · 07-15-2016, 11:29 AM

Success! I still suspect there was either a bug in the cmake stuff or something obvious I wasn't doing. But thanks for the tips everyone.

I'll try cleaning up the installation a bit now, but for future googlers the general steps were:
1. Install as per first post, but in the proper directory as NevemTeve said.
2. Fix file permissions and make sure ldconfig -v is finding the .so
3. Your compilation command might end up looking like this:
g++ example2.cpp -std=gnu++11 -I/usr/include/SDL -I/usr/local/lib/nanogui-sdl -I/usr/local/lib/nanogui-sdl/ext/eigen/ -D_GNU_SOURCE=1 -D_REENTRANT -lSDL2 -L/usr/local/lib -lnanogui

So it's a good idea to use a script or a makefile. My mistake was just not being thorough enough in tracking down all of the places I needed to include. Good learning experience, as always.

crazy-yiuf · 07-15-2016, 12:54 PM

I spoke too soon. The binary I compile only runs about one in every twenty times. The other 19/20 it segfaults. Gdb says:

Code:

(gdb) run
Starting program: /home/developer/src/sdlGame/a.out 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffe9bd0700 (LWP 3738)]

Thread 1 "a.out" received signal SIGSEGV, Segmentation fault.
0x0000000500000068 in ?? ()
(gdb) backtrace
#0  0x0000000500000068 in ?? ()
#1  0x0000000000405e3f in std::_Function_base::~_Function_base (this=0x7fffffffdba0, 
    __in_chrg=<optimized out>) at /usr/include/c++/5/functional:1830
#2  0x0000000000406592 in std::function<void (int)>::~function() (this=0x7fffffffdba0, 
    __in_chrg=<optimized out>) at /usr/include/c++/5/functional:1974
#3  0x000000000040803c in std::function<void (int)>::operator=(std::function<void (int)> const&) (
    this=0xd34638, __x=...) at /usr/include/c++/5/functional:2071
#4  0x00000000004065c0 in nanogui::ComboBox::setCallback(std::function<void (int)> const&) (
    this=0xd344a0, callback=...) at /usr/local/lib/nanogui-sdl/include/combobox.h:36
#5  0x0000000000410a14 in nanogui::detail::FormWidget<test_enum, std::integral_constant<bool, true> >::setCallback(std::function<void (test_enum)> const&) (this=0xd344a0, cb=...)
    at /usr/local/lib/nanogui-sdl/include/formhelper.h:216
#6  0x000000000040c899 in nanogui::FormHelper::addVariable<test_enum>(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::function<void (test_enum)> const&, std::function<test_enum ()> const&, bool) (this=0xd1d4c0, label="Enumeration", setter=..., getter=..., 
    editable=true) at /usr/local/lib/nanogui-sdl/include/formhelper.h:103
#7  0x0000000000408f49 in nanogui::FormHelper::addVariable<test_enum> (this=0xd1d4c0, 
    label="Enumeration", value=@0x629650: Item2, editable=true)
    at /usr/local/lib/nanogui-sdl/include/formhelper.h:125
#8  0x0000000000405114 in main () at example2.cpp:115

Which is very strange since the binary that running "make" created from the exact same source file runs every time. I compare the ldd output of the two, and they are loaded in a different order. Should that make a difference? If I sort the ldd output and compare the first 27 characters they are identical.

I guess I'll try reinstalling it a bit differently later, so I'll leave the thread marked as solved, but any thoughts are appreciated in the mean time. The contents of the nanogui directory are:

Code:

developer /usr/local/lib/nanogui-sdl $ ls
bin2c           cmake_install.cmake  example2  include        Makefile               README.md
CMakeCache.txt  CMakeLists.txt       ext       libnanogui.so  nanogui_resources.cpp  resources
CMakeFiles      example1             icons     LICENSE.txt    nanogui_resources.h    src

make install gives:
make: *** No rule to make target 'install'. Stop.

But it certainly feels like I'm missing some sort of install command. I'll be happy to post the contents any of these files on pastebin, but I can't make heads or tails of them.

I've tried a few more things and I'm stumped, so reopening question.

NevemTeve · 07-15-2016, 01:49 PM

I think the developer might have forgotten about the installation part, which usually comes between compilation and usage. That happens even to the best of programmers sometimes. You could file a bug-report/feature-request.

Edit:
Also libnanogui.so is created with no major/minor version numbers.

These bits wouldn't matter in Windows, but as it is Unix, I suggest non-using this (otherwise brilliant) product for now.

crazy-yiuf · 07-15-2016, 02:15 PM

Haha, yes, I suspect you're right, though I've seen at least one case of it working on Linux.

Earlier I tried making up some major and minor versions with no luck. I'll pester the dev when I get a chance.

NevemTeve · 07-15-2016, 03:13 PM

Note1: there's two other useful unix-tools that could be suggested to the author: libtool and pkg-config
Note2: most likely your problem could be easily debugged, if it weren't in C++. The awesome features of C++ like templates and overloading makes it hard to debug.

crazy-yiuf · 07-15-2016, 06:53 PM

It occurred to me that I probably should have tried Valgrind before now. It works perfectly when it's running in Valgrind! Here's the basic output
http://paste.debian.net/781864/

and the -v --track-origins output:
http://paste.debian.net/781865/

I linked this thread in my issue report, so I'll note here that I'm using ratpoison as a window manager and the SDL window doesn't automatically full screen (which is fine, I just don't know if it could be related somehow).

Edit: those were for example2.cpp. Example1 still dies in Valgrind and outputs "killed":
http://paste.debian.net/781867/

Edit: the tried and true "add a ton of cout" debugger indicates the problem starts with this line in example2
ref<Window> rwindow = gui->addWindow(Eigen::Vector2i(10, 10), "Form helper example");

norobro · 07-15-2016, 09:54 PM

First a question. Did you perform a debug build of the library? I ask because of the "optimized out" in the backtrace.

Code:

cmake -DCMAKE_BUILD_TYPE=DEBUG ..

Looking through the CMakeLists.txt file in the root directory of that library, I noticed the following:

Code:

if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
  # Enable C++11 mode on GCC / Clang
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
  add_definitions( -DEIGEN_DONT_ALIGN )
endif()

You might try adding -DEIGEN_DONT_ALIGN to your command line.

ntubski · 07-16-2016, 07:42 AM

Quote:

Originally Posted by norobro

First a question. Did you perform a debug build of the library? I ask because of the "optimized out" in the backtrace.

Also, with debugging info, the valgrind errors should have line numbers which makes them much more useful.

crazy-yiuf · 07-16-2016, 11:58 AM

Quote:

Did you perform a debug build of the library? I ask because of the "optimized out" in the backtrace

I did not, it looks like I have a lot to learn about cmake. Simply running the code after following your instructions explained the problem clearly, I think:

Code:

a.out: /usr/local/src/nanogui-sdl/ext/eigen/Eigen/src/Core/DenseStorage.h:86: Eigen::internal::plain_array<T, Size, MatrixOrArrayOptions, 16>::plain_array() [with T = float; int Size = 4; int MatrixOrArrayOptions = 0]: Assertion `(reinterpret_cast<size_t>(eigen_unaligned_array_assert_workaround_gcc47(array)) & 0xf) == 0 && "this assertion is explained here: " "http://eigen.tuxfamily.org/dox-devel/group__TopicUnalignedArrayAssert.html" " **** READ THIS WEB PAGE !!! ****"' failed.
Aborted

And -DEIGEN_DONT_ALIGN fixed it! Brilliant. I'll suggest adding it to the github readme. Thank you everyone, now I can start on my project

To put it in a fool-proof summary, this should basically work:
su
apt-get install cmake xorg-dev libglu1-mesa-dev libsdl2.0
cd /usr/local/src
git clone --recursive https://github.com/dalerank/nanogui-sdl
cd nanogui-sdl
cmake ./
make
cp src/example2.cpp ./
g++ example2.cpp -std=gnu++11 `sdl2-config --cflags --libs` -I/usr/local/src/nanogui-sdl -I/usr/local/src/nanogui-sdl/ext/eigen/ -DEIGEN_DONT_ALIGN -L/usr/local/src/nanogui-sdl -lnanogui
export LD_LIBRARY_PATH=/usr/local/src
./a.out

Cleaning it up and compiling from your home directory is left as an exercise for the reader.