I have an application that relies on Qt, GDCM, and VTK, with the main build environment being Qt. All of these libraries are cross-platform and compile on Windows, Mac, and Linux. I need to deploy the application to Linux after deploying on Windows. The versions of vtk and gdcm I'm using are trunk versions from git (about a month old), more recent than what I can get apt-get on Ubuntu 11.04, which is my current (and only) Linux deployment target.
What is the accepted method for deploying an application that relies on these kinds of libraries?
Should I be statically linking here, to avoid LD_LIBRARY_PATH? I see conflicting reports on LD_LIBRARY_PATH; tutorials like this one suggest that it's the 'right way' to modify the library path to use shared libraries through system reboots. Others suggest that I should never set LD_LIBRARY_PATH. In the default version of GDCM, the installation already puts libraries into the /usr/local/lib directory, so those libraries get seen when I run ldd <my program>. VTK, on the other hand, puts its libraries into /usr/local/lib/vtk-5.9, which is not part of the LD_LIBRARY_PATH on most user's machines, and so is not found unless some change is made to the system. Copying the VTK files into '/usr/local/lib' does not allow 'ldd' to see the files.
So, how can I make my application see VTK to use the libraries?
On windows, deploying the dlls is very straightforward, because I can just include them in the installer, and the application finds them because they are in the local directory. That approach does not work in Linux, so I was going to have the users install Qt, GDCM, and VTK from whatever appropriate source and use the default locations, and then have the application point to those default locations. However, since VTK is putting things into a non-standard location, should I also expect users to modify LD_LIBRARY_PATH? Should I include the specific versions of the libraries that I want and then figure out how to make the executable look in the local directory for those libraries and ignore the ones it finds in the library path?
Every "serious" commercial application I have ever seen uses LD_LIBRARY_PATH. They invariably include a shell script that looks something like this:
#!/bin/sh
here="${0%/*}" # or you can use `dirname "$0"`
LD_LIBRARY_PATH="$here"/lib:"$LD_LIBRARY_PATH"
export LD_LIBRARY_PATH
exec "$0".bin "$#"
They name this script something like .wrapper and create a directory tree that looks like this:
.wrapper
lib/ (directory full of .so files)
app1 -> .wrapper (symlink)
app1.bin (executable)
app2 -> .wrapper (symlink)
app2.bin (executable)
Now you can copy this whole tree to wherever you want, and you can run "/path/to/tree/app1" or "/path/to/tree/app2 --with --some --arguments" and it will work. So will putting /path/to/tree in your PATH.
Incidentally, this is also how Firefox and Chrome do it, more or less.
Whoever told you not to use LD_LIBRARY_PATH is full of it, IMHO.
Which system libraries you want to put in lib depends on which Linux versions you want to officially support.
Do not even think about static linking. The glibc developers do not like it, they do not care about supporting it, and they somehow manage to break it a little harder with every release.
Good luck.
In general, you're best off depending on the 'normal' versions of the libraries for whatever distribution you're targetting (and saying you don't support dists that don't support recent enough versions of the lib), but if you REALLY need to depend on a bleeding edge version of some shared lib, you can link your app with -Wl,-rpath,'$ORIGIN' and then install a copy of the exact version you want in the same directory as your executable.
Note that if you use make, you'll need $$ in the makefile to get a single $ into the argument that is actually sent to the linker. The single qutoes are needed so the shell doesn't munge things...
Well, there are two options for deploying Linux application.
The correct way:
make a package for your app and for the libraries, if they are so special, that they can't be installed from standard repositories
There are two major package formats. RPM and DEB.
The easy way:
make a self-extract file that will install the "windows way" into /opt.
You can have libraries in the same directory as the executable, it's just not the preferred way.
Related
This should be really simple, but I'm having trouble. I want to include some shared Qt libraries with my application in the installation folder so the user doesn't have to download Qt separately. On Windows, this seemed to work fine, but Ubuntu complains about not being to find the Qt libraries when they are in the same folder as the application.
How do I add the installation directory to shared library search path?
I was able to add the installation directory to shared library search path by adding the following lines to the .pro file, which set the rpath of the binary to $ORIGIN (the install folder). I needed to add the location of QT libs on my current machine (/usr/lib/qt5.5 and /usr/lib/qt5.5/lib) so that the project would build in QtCreator.
unix:!macx {
# suppress the default RPATH if you wish
QMAKE_LFLAGS_RPATH=
# add your own with quoting gyrations to make sure $ORIGIN gets to the command line unexpanded
QMAKE_LFLAGS += "-Wl,-rpath,\'\$$ORIGIN\':/usr/lib/qt5.5:/usr/lib/qt5.5/lib"
}
(The unix:!macx line makes it apply to linux only)
Windows, Linux and OSX behave quite differently. Windows is easiest: dump all the dll's in the application dir. OSX is next and Linux is most difficult.
Linux has certain search paths for searching shared objects. These search paths are mainly system libraries and possibly some user libraries. As you do not want to mess around with system files of your user one would prefer to have the shared objects in the application dir. This is possible but you have to tell Linux to read that directory. You can do this with setting the environment variable LD_LIBRARY_PATH. You can do this with a script. See my answer.
I'm zipping a pre-built (no source/object files) binary application for distribution. The binary application requires a couple of libraries not included by default. The only way I seem to be able to get the application to start on the end-user is by including a run.sh that sets the library path to the current directory:
export LD_LIBRARY_PATH=./:$LD_LIBRARY_PATH
./MyApp.out
However, I'd really like to allow the user to just unzip the zip and doubleclick MyApp.out (without the shell script). Can I edit MyApp.out to search the current directory for the library? I've done something similar on OSX using install_name_tool, but that tool isn't available here.
You want to set the rpath. See this answer. So link using
gcc yourobjects*.o -L/some/lib/dir/ -lsome -Wl,-rpath,.
But you might want even to use -Wl,-rpath,$PWD or perhaps -Wl,-rpath,'$ORIGIN'. See this.
You could also (and this should work for a pre-built executable) configure your /etc/ld.so.conf by adding a line there with an absolute path (of the directory containing the lib), then running ldconfig -v ... See ldconfig(8)
I would suggest adding /usr/local/lib into /etc/ld.so.conf and making a symlink from /usr/local/lib/libfoo.so to e.g. $HOME/libfoo.so etc... (then run ldconfig ...). I don't think adding a user specific directory to /etc/ld.so.conf is reasonable ...
PS. What you really want is to package your application (e.g. as a *.deb package for Debian or Ubuntu, or an *.rpm for Fedora or Redhat). Package management systems handle dependencies!
In short: This question is basically about telling Linux to load the development version of the .so file for executables in the dev directory and the installed .so file for others.
In long: Imagine a shared library, let's call it libasdf.so. And imagine the following directories:
/home/user/asdf/lib: libasdf.so
/home/user/asdf/test: ... perform_test
/opt/asdf/lib: libasdf.so
/home/user/jkl: ... use_asdf
In other words, you have a development directory for your library (/home/user/asdf) and you have an installed copy of its previous stable version (/opt/asdf) and some other programs using it (/home/user/jkl).
My question is, how can I tell Linux, to load /home/user/asdf/lib/libasdf.so when executing /home/user/asdf/test/perform_test and to load /opt/asdf/lib/libasdf.so when executing /home/user/jkl/use_asdf? Note that, even though I specify the directory by -L during link, Linux uses other methods (for example /ect/ld.so.conf and $LD_LIBRARY_PATH) to find the .so file.
The reason I need such a thing is that, of course the executables in the development directory need to link with the latest version of the library, while the other programs, would want to use the stable version.
Putting ../lib in the library path doesn't seem like a secure idea, not to mention not completely correct since you can't run the test from a different directory.
One solution I thought about is to have perform_test link with libasdf-dev.so and upon install, copy libasdf-dev.so as libasdf.so and have others link with that. This solution has one problem though. Imagine the following additional directory:
/home/user/asdf/tool: ... use_asdf_too
Which gets installed to:
/opt/asdf/bin: use_asdf_too
In my solution, it is unknown what use_asdf_too should be linked against. If linked against libasdf.so, it wouldn't work properly if invoked from the dev directory and if linked against libasdf-dev.so, it wouldn't work properly if invoked from the installed location.
What can I do? How is this managed by other people?
Installed shared objects usually don't just end with ".so". Usually they also include their soname, such as libadsf.so.42.1. The .so file for development is typically a symlink to a fully-versioned filename. The linker will look for the .so file and resolve it to the full filename, and the loader will then load the fully-versioned library instead.
I have some shared/dynamic libraries installed in a sandbox directory. I'm building some applications which link agains the libraries. I'm running into what appears to be a difference between OSX and Linux in this regard and I'm not sure what the (best) solution is.
On OSX the location of library itself is recorded into the library, so that if your applications links against it, the executable knows where to look for the library at runtime. This works like expected with my sandbox, because the executable looks there instead of system wide install paths.
On Linux I can't get this to work. Apparently the library location is not present in the library itself. As I understand it you have to add the folders which contain libraries to /etc/ld.so.conf and regenerate the ld cache by running ldconfig.
This doesn't seem to do the trick for me because my libraries are located inside a users home directory. It looks like ldconfig doesn't like that, which makes sense actually.
How can I solve this? I don't want to move the libraries out of my sandbox.
On Linux, run your program with the environment variable LD_LIBRARY_PATH set to your sandbox dir.
(I remember having used a flag -R to include library paths in the binary, but either it has been removed from gcc or it was only available on BSD systems.)
On Linux you should set LD_RUN_PATH to your sandbox dir. This is better than setting LD_LIBRARY_PATH because you're telling the linker where the library is at link time, rather than telling the shared library loader at run time.
See: Link
I'm trying to build a Win32 DLL from an audio-DSP related Linux library (http://breakfastquay.com/rubberband/). There are makefiles and config scripts for Linux, but no help for Windows. The author provides a Win32 binary of a sample app using the library, and I see a number of "#ifdef MSVC" and "#ifdef WIN32" scattered around, so I don't think I'm starting completely from scratch but I'm stuck nevertheless.
As my programming knowledge in either platform is rather limited, I'd appreciate any help.
First of all, what is the right way to get started here? Visual Studio? Cygwin? Initially I started off creating a Win32 DLL project in Visual Studio, adding the source files, thinking about adding a .def file, etc, but at some point I felt like this was going nowhere.
As for Cygwin, this was the first time using it, and I don't even know if this is the sort of thing that Cygwin is designed for. Is it?
On Cygwin, I ran ./configure and got stuck at something like this:
"checking for SRC... configure: error: Package requirements (samplerate) were not met: No package 'samplerate' found"
After looking through the log, it appears that pkg-config is looking for samplerate.pc. How do I handle packages in Windows? libsamplerate is just an open source library, and I have source and a DLL for this. But I'm not sure how to use them to satisfy the dependency requirements for librubberband (which is what I'm trying to build)
I'm completely lost at this point and if anyone can give me a nudge in the right direction... and, is there an easier way to do this?
Many thanks in advance.
If you're still stuck on this I can throw a little light.
You may have to build everything from sources (or have the libraries installed in your environment). You're using Cygwin, I would recommend MinGW and MSYS too, but sometimes it's just not possible to use this combination to build the program or library.
So if using Cygwin, first ensure that you have a proper environment installed. This is that you have the correct development headers installed.
Then download libsndfile. Extract the sources to a directory and from the Cygwin bash shell navigate to that directory. There perform:
./configure
make
make install prefix=/cygdrive/c/cygwin
Notice that I use a prefix, that prefix should point to the directory Cygwin is installed in order to correctly install the libraries (the same happens to MinGW and MSYS, the prefix should point to the MinGW installation directory). Maybe using the usr directory in the prefix works too, I've never tried it.
Now download FFTW, as it will be needed for libsamplerate and rubberband. Same procedure as with libsndfile: extract, configure, make & make install using the prefix. Now copy the header files of FFTW (in the example they'd be in /cygdrive/c/cygwin/include) to the include directory in the usr directory (in the example /cygdrive/c/cygwin/usr/include).
Next SRC (libsamplerate), same procedure.
Then the Vamp plugin SDK. In order to compile the it you may need to edit the file src\vamp-hostsdk\PluginLoader.cpp, deleting RTLD_LOCAL from a dlopen() call (it's safe, it's already the default behaviour).
Also, you may need to install it by hand (in my experiences it didn't like the prefix). Or set the environmental variable PKG_CONFIG_PATH pointing to the paths of pkgconfig, e.g.:
set PKG_CONFIG_PATH=/cygdrive/c/cygwin/lib/pkgconfig:/usr/local/lib/pkgconfig
Now, create a file called ladspa.h in the include directory with the contents of the LADSPA header
Finally, configure and build rubberband, it should find everything it needs.
To build in MSYS using MinGW follow the same procedure, using the according prefix. Using Visual Studio is another alternative, but you may need to use some of the pre-built libraries (for example for libsndfile) as building Linux libraries natively in Windows may be complicated or even impossible (without hacking the source code) in VS.
Anyway, the autor of rubberband provides binaries; I think you should consider use them instead of going through all of this.
Linux to w32 is mostly a tricky thing.
For each of your dependencies, download the source and:
./configure
make
sudo make install
Also, I recommend you to use MinGW + msys in place of CygWin (as the latter produces executables that depend on its libraries). However in your situtation, use the VS approach -- 't will save you a lot of time.