I have built gcc-4.8.2 from source code, configured with --prefix=.../destdir. I'm using Ubuntu 12.04 64-bit.
So after I ran 'make' and 'make install' all the libraries where built and put to
.../destdir/lib/gcc/x86_64-unknown-linux-gnu/4.8.2.
And I also have newly built g++ and gcc in
.../destdir/bin
the question is, if I try to build a program with .../destdir/bin/g++ will use the newly made libraries when linking, or the ones located in standard paths?
If latter, what is the best way to make it linkt against the new ones, or is there a way to know what libs are used?
By default it will use the right libraries at link time, but not at run time.
To use the right libraries at run time, either add -Wl,-rpath=/absolute/path/to/your/libraries to your link command (recommended), or add that directory to your $LD_LIBRARY_PATH (a quick-and-dirty workaround).
Related
I have completed a small project that uses several libraries. the CMakeList.txt looks like this:
cmake_minimum_required(VERSION 3.5)
project(tf_ct_log C)
set(CMAKE_C_STANDARD 99)
include_directories(include /usr/local/include/hiredis /usr/include/openssl)
link_directories(/usr/lib/x86_64-linux-gnu)
set(HDR include/ct_logger.h)
add_executable(tf_ct_logger src/main.c src/ct_logger.c ${HDR})
find_package(OpenSSL REQUIRED)
find_package(Threads REQUIRED)
find_library(PostgreSQL REQUIRED)
find_library(jansson REQUIRED)
target_link_libraries(tf_ct_logger OpenSSL::SSL jansson pthread pq)
I would like to be able to build a package that can be installed in another machine, without downloading any dependencies. with ldd, I 've got all dependencies of the application and copied those files (libxyz.so...) into a subdirectory deps in my project. How can I create that package using those dependencies so that the end user will just use the object files of my project along with the dependencies libraries to create the executable?
It gets really hairy real quick when you need to create a native package for multiple flavors of installers (Debian, RH, Arch, etc.), especially if customization is involved.
If you just need a clean reproducible to get it on a box and run -- I would strongly suggest looking towards packaging it as a Docker container.
You start from some lightweight Linux distro container (Alpine is the latest trend), derive it into one with C and C++ runtime and anything else you depend on and call this "my prod container". From that you derive one with C++ compiler and debugger installed and call it "my dev container".
We actually wrote a little memo a while back, while making our open source hobby usable for others.
You will probably still need to clean up your CMake file to an extent that the "install" target works (mine is here).
I may have not expressed myself correctly. I just wanted to compile and build executables from my project, then find a way to copy it on another machine without having to install all dependencies before running the app.
The solution I found (with the help of a more experienced developer) was as follows:
1- Get all dependencies using ldd
2- Copy dependencies in a directory dependencies
3- On the target environment, copy content of dependencies into /usr/local/lib/myapp/
4- On the target environment, goto /etc/ld.so.conf.d/
5- create the file myapp.conf with one line in it: /usr/local/lib/myapp
6- run ldconfig
Then, the executable I created on my development machine runs here smoothly!
Of course all the steps I described up there must be listed in a script for automation
I have been trying to do build and use OpenCV 2.3.0 on my Fedora15 Lovelock 64bit machine.
Background:
First, on my 64bit Fedora15, OpenCV2.2.0 seems to be in the locations namely
/usr/share/opencv
/usr/doc
/usr/lib64 &
/usr/bin
I do not find the include files though (in /usr/include). This means that the development package was n t installed. My package manager does not list the development packages when i try to Add/remove software.
I have a need to create applications, some of which just link to 2.2 and others which link to 2.3.O of the OpenCV library.So, I thought the best solution would be to have a separate location for 3rd party libraries that i use for my development . So I created a directory in /local named soft and created an OpenCV directory. A directory structure like this one.
/local/soft/
OpenCV/
OpenCV2.2.0/
source-files
build
OpenCV2.3.0/
source-files
build
installation
share/opencv
doc
include
lib
Now, i tried building OpenCV2.3.0 and i succeeded. I configure CMake to use CMAKE_INSTALL_PREFIX to the directory named "installation" (see above), instead of the default /usr/local/. Clean. huh?
I tried building and installing OpenCv 2.2.0 in the same way. Alas 2.2.0 complains something during the build. So i thought i ll link to the already existing version in the standard locations. BUT, when i try to install the dev packages for 2.2 using my package manager,the development files for x86_64 are not found :-) which means i dont have the headers to link to the libraries in the standard location.
I cant build my executable since linker ld would not find the OpenCV that i have installed in the non-standard location.(although i point it to the exact location using the -L and -l options with gcc in my Eclipse).
Question 1: Am i doing the right thing in maintaining installations in non-standard locations? Is /usr/ the standard location where the package manager will always do the installation?
Question2 : What is the right way of linking to these libraries installed in non-standard locations? Why would not ld recognize my .so files in the lib folder?
sudo g++ logpolar.cpp -o logpolar.o -I /local/soft/OpenCV/opencv2.3.1/installation/include/ -l/local/soft/OpenCV/opencv2.3.1/build/lib/libopencv_core.so
But ld canot find -l/local/soft/OpenCV/opencv2.3.1/build/lib/libopencv_core.so
I checked the lib folder and there sure is a beautiful symbolic link to libopencv_core.so.2.3
The standard approach is to use /usr/local directory structure that already has predefined paths like /usr/local/bin, /usr/local/sbin, /usr/local/include, /usr/local/lib.
You put your software here and everything will JustWork(TM). Every Linux distro (incl. Fedora) is set up so it will load programs (libraries, headers) from this libraries.
If you would use GNU toolchain (autoconf, automake => autotools) you would be fine. With CMake you probably need to setup paths for /usr/local/include and /usr/local/lib.
On the other hand this approach wont let you use multiple versions. You can only have one. The one in /usr/local overrides the system one (installed in /usr/bin) because these paths goes first.
You can keep your approach, it is nothing incorrect. We usually put such a software in the /opt folder, so you would go for /opt/opencv/X.Y where X.Y are the version numbers.
Q2: Read the gcc man page and search for the -L option. You need something like:
gcc ... -I/opt/opencv/2.0/include -lsystem_lib -L/opt/opencv/2.0/lib -lopencv ... ...
Do not forget to set LD_LIBRARY_PATH when running programs in multiple versions to properly load correct version:
LD_LIBRARY_PATH=/opt/opencv/2.0/lib /opt/opencv/2.0/bin/opencv
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.
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.