I want to set up LEDA library in my system.
I have downloaded LEDA library from the following link
http://www.algorithmic-solutions.info/free/d5.php
Instruction given in read me file
2. Preparations
---------------
Unpacking the LEDA distribution file
LEDA---.tar.gz will create the LEDA root
directory "LEDA---". You might want to rename
it or move it to some different place. Let denote the final
complete path name of the LEDA root directory.
To install and use the Unix object code of LEDA you have to modify
your environment as follows:
a) LEDAROOT:
Set the environment variable LEDAROOT to the LEDA root directory:
csh/tcsh: setenv LEDAROOT
sh/bash: LEDAROOT=
export LEDAROOT
b) Command Search Path:
Include $LEDAROOT/Manual/cmd into your command search path
(environment variable path (csh) or PATH (sh)) and call rehash (if
required by your system).
c) Shared Library: (for solaris, linux, irix, osf1)
If you planning to use shared libraries include $LEDAROOT into the
LD_LIBRARY_PATH search path. Then go to $LEDAROOT and type
make shared. This will construct the shared libraries from the static
libraries.
Please note: Building the shared library is not supported on each
platform.
d) xlman and demos: Go to $LEDAROOT and type make xlman to compile
and link LEDA's interactive manual reader xlman. Now you can start
xlman for reading and printing manual pages, starting demo programs
and browsing more release notes.
3. Compiling and linking application programs
---------------------------------------------
a) Use the -I compiler flag to tell the compiler where to find the
LEDA header files.
CC (g++) -I$LEDAROOT/incl -c file.c
b) Use the -L compiler flag to tell the compiler where to find the
library (libleda.a/so)
CC (g++) -L$LEDAROOT file.o -lleda -lX11 -lm
If using windows on solaris systems you might have to link
with the system socket library and the network services library as
well:
CC (g++) ... -lleda -lX11 -lsocket -lnsl -lm
c) Compile and link simultaneously with
CC (g++) -I$LEDAROOT/incl -L$LEDAROOT file.c -lleda -lX11 -lm
You may want to ask your system adminstrator to install the header
files and library in the system's default directories.
Then you no longer have to specify header and library search paths on
the compiler command line.
I followed these instruction but I got error in command
> make xlman
error
coredump#coredump-VPCCB15FG:~/Documents/LEDA$ make xlman
make -C demo/xlman
make: *** demo/xlman: No such file or directory. Stop.
make: *** [xlman] Error 2
someone please help me to setup library.
NOTE: For the free version of the Leda library, you don't have to build the package to use the library. It simply doesn't work.
To use the library simply include it in your compile line and linker.
If you are compiling from the shell (assuming you are using Linux), do the following:
1. Set the env variable to the library folder e.g export LEDAROOT= /path/to/Leda
2. Set the LD_LIBRARY_PATH env variable e.g export LD_LIBRARY_PATH=$LEDAROOT
Verify that this variables are set then you can compile and link and run. You can simply do
CC (g++) -I$LEDAROOT/incl -L$LEDAROOT file.c -lleda -lX11 -lm
With this you should be good to go.
If you are using an IDE, simply add the include path (i.e /path/to/leda) to you project settings.
This is all you have to do. Building the library does not work. Simply include it
Related
I'm compiling a c++ program using g++ and i am using two libraries called libsdl2-dev and libsdl2-image-dev
I installed both these libraries in my ubuntu machine with the commands
apt install libsdl2-dev libsdl2-image-dev and when I compile the program everything works fine. Then I copied these libraries from /usr/lib/x86_64-linux-gnu/ to my working dir with the binary file to be able to give this folder to someone else.
The problem comes when the user that hasn't installed these libraries tries to open my program by writing ./main (the binary file). Since he hasn't installed these libraries he would get an error like "can't open shared object: no such file or directory".
This happens because the binary file looks for these libraries in /usr/lib etc...
What i need
I need that my binary file looks for these libraries in the same folder,and not in /usr/lib/x86 etc.., from what I read I have to do something like rpath
The IDE used is Sublime Text and the syntax used to compile all my files is this:
g++ -c src/*.cpp -std=c++14 -m64 -g -Wall -I include && g++ *.o -o bin/debug/main -lSDL2main -lSDL2 -lSDL2_image && ./bin/debug/main`
Structure of folders
I got the project dir with and inside that i got 4 more directories, each one called: bin (with the debug subdirectory, where we got the final compile), include (with hpp files), res (with all textures), and src with all cpp files to compile, the other files are project files and .o files
I'm using Ubuntu 20.04-2 LTS and the same is for the other user's PC
Thanks in advance for any help!
That's because the dynamic linker loading runtime dependencies looks for them in some specified locations, which are "by default" your system library directories (where those libraries got installed by apt).
The other user should ideally install those libraries too (which could be done "automatically" if you build a .deb package with proper dependencies)
Otherwise you would have to change the runpath of your program by adding -Wl,-rpath='$ORIGIN', which makes the dynamic linker look for dependencies just where the binary is located.
$ORIGIN here is a special variable meaning "this executable" which is what you wanted to achieve.
see rpath
and A description of RPATH $ORIGIN
I found a way to resolve!
I used the program patchelf to add an rpath to my directory (linked to the binary file) now everything works
use ldd ./bin/debug/main to check the library
export LD_LIBRARY_PATH =$LD_LIBRARY_PATH:"your library path"
run the program,if this is not work. use patchelf to change the rpath to you r library
I'm trying to compile a shared library I wrote in C++ to use a specific version of another shared library in the current directory, however it seems to be ignoring that and it uses the (older and incompatible) .so file in my LD_LIBRARY_PATH at runtime. How would I go about overriding the .so file it uses to use my own? I also need to retain the older version for another use on the same system.
Here's my command I'm using to compile: clang++ /data/openpilot/selfdrive/df/libs/libSNPE.so -lsymphony-cpu -lsymphonypower -I/data/openpilot/phonelibs/snpe/include -std=c++14 -lstdc++ -fPIC -o d_f.so dynamic_follow.cc -shared
/data/openpilot/selfdrive/df/libs/libSNPE.so being the library I want to use.
I also tried to use the -l flag before my library file, however it returns cannot find -l/data/openpilot/selfdrive/df/libs/libSNPE.so
Confirmed to still use the library in LD_LIBRARY_PATH with this command as well: clang++ -Wl,-rpath,/data/openpilot/selfdrive/df/libs -L/data/openpilot/selfdrive/df/libs -lSNPE -lsymphony-cpu -lsymphonypower -I/data/openpilot/phonelibs/snpe/include -std=c++14 -stdlib=libc++ -fPIC -o d_f.so dynamic_follow.cc -shared
The -L flag tells where to look for libraries at link time, while LD_LIBRARY_PATH tells where to look for libraries at run-time. So whatever path you set at link-time, this will be ignored when running the executable.
You need to have LD_LIBRARY_PATH include the directory of your dynamic library at run-time for your executable to find it. So you may run your executable like this:
LD_LIBRARY_PATH=/data/openpilot/selfdrive/df/libs:"$LD_LIBRARY_PATH" ./your-exec
The below compiles:
g++ -L../../lib -o my_prog my_prog.cpp -ltest1 -ltest2
where ../../lib contains symlinks to libtest1.so and libtest2.so
But I am getting an error when I run the program: "error while loading shared libraries: libtest1.so: cannot open shared object file: No such file or directory" and am not sure if symlinking is the culprit.
Option -L is for linker ld to find .a and .so during linking.
Option -Wl,-rpath= is for the dynamic linker ld.so to find .so when the application is run. You need to use -Wl,-rpath= when a required shared library is not in (standard system) directories specified in /etc/ld.so.conf.
Use $ORIGIN dynamic linker variable to make rpath relative to the path of your executable:
g++ -L../../lib -Wl,-rpath='${ORIGIN}/../../lib' -o my_prog my_prog.cpp -ltest1 -ltest2
Be careful to make sure ${ORIGIN} is not expanded by the shell or your makefile (this is why it is in single quotes).
${ORIGIN}:
$ORIGIN and rpath
ld.so understands the string $ORIGIN (or equivalently ${ORIGIN}) in an rpath specification (DT_RPATH or DT_RUNPATH) to mean the directory containing the application executable. Thus, an application located in somedir/app could be compiled with gcc -Wl,-rpath,'$ORIGIN/../lib' so that it finds an associated shared library in somedir/lib no matter where somedir is located in the directory hierarchy. This facilitates the creation of "turn-key" applications that do not need to be installed into special directories, but can instead be unpacked into any directory and still find their own shared libraries.
What happens at runtime is related to the rpath.
You may want (not really recommended, see this) to set your LD_LIBRARY_PATH appropriately before running your executable, or better yet you want to set the executable's rpath when linking it (e.g. by passing -Wl,--rpath $(realpath ../../lib/) to the g++ command doing the link.
Read Drepper's How to write shared libraries paper and the Program Library HowTo
I have the following problem:
I have two separate c++ projects, and want to use certain functions from one of them in the other. I am compiling using g++, on Linux.
I decided to do this by creating a shared library out of the project from which to use the functions. I added -fPIC to the compiler flags in the Makefile and then created a shared library like this:
g++ -shared -Wl,-soname,libmyproject.so.1 -o libmyproject.so a.o b.o c.o -lc
Then I simply copied the .so file and the header files into the (parent) directory of the new project and added the following to its Makefile:
To LIBS:
-L/../external_proj/libmyproject.so
To CXXFLAGS:
-I/../external_proj
Then I #include the appropriate header file in the destination project code and try to call certain functions from the original project. However, when I compile the destination project I get an error "undefined reference" for the imported function.
My question is then: is there something I'm missing in this setup? Is there perhaps something that needs to be added to the headers in the original project in order to export the functions I want to use?
I should note this is the first time I have attempted to use a shared library in this way. Thanks.
The -L option only specifies the directory where the linker will search for libraries to link with. Then you will need to use the -l option to specify the base name of the shared library (without the "lib" prefix and the ".so" suffix).
But even that will unlikely to be enough. The runtime loader needs to find the shared library, when you attempt to try to execute it. -L and -l will be sufficient to successfully link, but the runtime loader only searches /usr/lib(64)?, and a few other places by default. It does NOT search the current directory, and the ELF binary only records the names of the shared libraries that must be loaded, and not their full pathnames. You have to explicitly record any extra directories to search for any shared libraries, which is the -rpath option.
To finish the job you will also need to pass -rpath to the linker, but g++ does not support this option directory, you will have to use -W to do that.
The full set of options you will likely need are:
-L/../external_proj -lmyproject -Wl,-rpath -Wl,`cd ../external_proj && pwd`
See gcc documentation for more information on the -W option.
Absolute pathnames should be used with -rpath, hence the need to obtain the full pathname to the directory where the shared library is.
The -L flag is to add a path to search libraries in. The -l (lower-case L) is for linking with a library in the search path.
Or you can skip the flags and link with the library directly, almost like you do now (but without the -L option).
If you use the -l option, then remember that for a file libname.so you use only name as the library name. As in -lname. The linker will search for the correct files with the added prefix and suffix.
And lastly an important note about the paths used when linking: If you use -L and -l to link with a shared library, it's only the linker which will find the library. The OS runtime-loader will not be able to see the path used and will not find the library, if it's in a non-standard location. For that you must also set the runtime-path using the special linker option -rpath.
Unfortunately the GCC frontend program g++ doesn't recognize that option, you have to use -Wl to tell g++ to pass on an option to the actual linker. As in -Wl,-rpath,/path/to/libraries.
To summarize, here are the different variants you can use:
Link directly with the library: g++ your_source.cpp ../external_proj/libmyproject.so
Use the -L and -l options: g++ your_source.cpp -L../external_proj -lmyproject
To set the runtime linker path: g++ your_source.cpp -L../external_proj -lmyproject -Wl,-rpath,../external_proj
I am trying to build and link a C++, cmake-based project with clang (3.0). This project links to several libraries that are installed in a custom directory /my/dir/. This directory is included in the LD_LIBRARY_PATH and LIBRARY_PATH environment variables. Project builds and links fine with g++.
The link command generated and executed by cmake looks like the following:
/usr/bin/clang++ -O3 stuff.cpp.o -o stuff -rdynamic -lmylib
ld then complains with the following message:
/usr/bin/ld: cannot find -lmylib
The link command above runs fine whenever I manually add -L/my/dir/. Is there a way to link without specifying the -L flag?
The $LD_LIBRARY_PATH environment variable (and its various alternatives on other UNIX-based platforms) is used at runtime, not link time, to find libraries.
Using -L is the correct approach and cannot be avoided.
Note: A better approach under Linux (you don't specify your platform so I'm guessing) is to correctly configure a file in /etc/ld.so.conf.d/ and avoid using $LD_LIBRARY_PATH altogether.