I'm trying to compile example from GnuTLS. I can compile GnuTLS with no problem.
I usually use this command when I have default GnuTLS package installed. I compile the example with this commend.
gcc -o server ex-serv-srp.c -lgnutls
I build GnuTLS from source. I can compile the example with the same command but when I try to run the example I get this error:
./server: error while loading shared libraries: libgnutls.so.28: cannot open shared object file: No such file or directory
The location of libgnutls.so.28 is in /usr/local/lib directory. How I can link the example during compilation time so that they will know where to find libgnutls.so.28
Regards
For a permanent solution add /usr/local/lib to /etc/ld.so.conf and rerun ldconfig, otherwise do as zvbra proposes.
You should set LD_LIBRARY_PATH variable like this export LD_LIBRARY_PATH=/usr/local/lib.
Related
I have a C application using CMake to generate Makefiles on Linux. The application contains .c as well as .proto files. Now I need to genearte .pb-c.c and .pb-c.h using protoc command in the CMakeLists.txt so that when I do cmake . the cmake generates the corresponding .pb-c and .pb-h. The protoc is used as:
execute_process(COMMAND bash -c "${PROTOC_PATH} --c_out=${CMAKE_CURRENT_SOURCE_DIR}/ --proto_path=${PROTO_DIR}/ ${PROTO_DIR}/*.proto")
The problem is that my protoc binary and related .so file is not in /usr/bin and /usr/lib or /usr/local/bin and /usr/local/lib. They are in a directory inside the project - $HOME/project-name/dependencies/bin/protoc and $HOME/project-name/dependencies/lib/libprotobuf.so.12
Due to this I am getting error - error while loading shared libraries: libprotobuf.so.12: cannot open shared object file: No such file or directory
But if I give the command as
execute_process(COMMAND bash -c "protoc--c_out=${CMAKE_CURRENT_SOURCE_DIR}/ --proto_path=${PROTO_DIR}/ ${PROTO_DIR}/*.proto") and run cmake . then it works fine as linker is able to get the .so file from /usr/lib
Mentioned below is a part of my CMakeLists.txt file
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-rpath=${PROTOC_LIB_PATH} -L${PROTOC_LIB_PATH} -lprotobuf")
set(CMAKE_SHARED_LINKER_FLAGS "-Wl,-rpath=${PROTOC_LIB_PATH} -L${PROTOC_LIB_PATH} -lprotobuf")
execute_process(COMMAND bash -c "${PROTOC_PATH} --c_out=${CMAKE_CURRENT_SOURCE_DIR}/ --proto_path=${PROTO_DIR}/ ${PROTO_DIR}/*.proto")
But it's not working due to aforementioned error.
Also for those who might say it's a duplicate I have looked into and tried the following SO questions:
Turning on linker flags with CMake
I don't understand -Wl,-rpath -Wl,
CMake link to external library
Does cmake have something like target_link_options?
CMAKE RPATH not working - could not find shared object file
https://serverfault.com/q/279068/435497
How to add linker flag for libraries with CMake?
https://serverfault.com/a/926072/435497
If you do not have a special use case, you do not need to call protoc yourself. Let CMake do this for you.
Have a look at: https://cmake.org/cmake/help/v3.16/module/FindProtobuf.html
and Cmake : find protobuf package in custom directory
I found this link which has a script showing how to create a PROTOBUF_GENERATE_C function which can then be used to generate the .pb-c abd .pb-h files.
From the above script I got the idea to make use of find_program which is similar to find_library in a way that it lets you pass the PATHS/PATH option so that CMake looks for the required program in the mentioned path.
I am trying to compile and run this code under ubuntu 14.04. I downloaded and installed libpng version 1.6.12. I am able to compile the code using gcc test.c -lpng but when I try to run it, I get this error:
./a.out: error while loading shared libraries: libpng16.so.16: cannot open shared object file: No such file or directory
edit:
So I found libpng16.so.16, it was in /usr/local/lib and I copied it to /usr/local/include/libpng16/ and as well to /usr/local/include/ and recompiled the code, anyway the problem still persists.
Any suggestions ?
Ok so I found the solution here. The trick is to run sudo ldconfig after you install some shared library.
You can download the library from the link
https://sourceforge.net/projects/libpng/?source=directory
It will download a file something like "libpng-1.6.32.tar.xz"
Simply extract the file go inside folder and run these commands to install
./configure
make check
make install
Then you need to run after installing any library
ldconfig
I had same problem before I had installed it form below link and problem fixed.
I hope yours would be fixed as well
PNG reference library: libpng
I'm trying to play an mp3 file in terminal using C and I followed this link to do so.
I've installed the two libraries libmpg123 and libao. Also, I've compiled the play.c program using the command:
gcc -O2 -o play play.c -lmpg123 -lao
But I get the following error when I run it:
./play: error while loading shared libraries: libao.so.4: cannot open shared object file: No such file or directory
Can you figure it out why it happened.
The executable can be linked, but at run-time, it cannot find the shared libraries. Add the libraries to your LD_LIBRARY_PATH so the program can find them at run time.
I've done this before a couple of times, but somehow I'm stuck this time. I have an executable "myapp" and a own shared library "mylib". In my cmakelists I have the following:
ADD_LIBRARY(mylib SHARED ${SOURCES_LIB})
INSTALL(TARGETS mylib DESTINATION .)
ADD_EXECUTABLE(myapp ${SOURCES_APP})
TARGET_LINK_LIBRARIES(myapp ${QT_LIBRARIES} mylib)
INSTALL(TARGETS myapp DESTINATION .)
Everything compiles and links correctly, but when I start myapp, I get the following error:
error while loading shared libraries: libmylib.so: cannot open shared object file: No such file or directory
The lib and the executable are present in the install directory. When I make my library static by changing the first line of the above cmakelists to:
ADD_LIBRARY(mylib STATIC ${SOURCES_LIB})
then everything works 100%.
Does anyone know what I'm doing wrong?
During the installation of your library and executable, the runtime paths to find the library are stripped from the executable. Therefore your library has to reside in the runtime library search path. For example under Linux, try to set LD_LIBRARY_PATH to the directory that contains the installed library when starting your executable.
This is a very common question about "make install". Actually, there are 3 ways to link a library to your executable file. First, you may use -l -L flags in simple cases. As Benjamin said you may use LD_LIRARY_PATH and write something like: export LD_LIBRARY_PATH=/usr/local/my_lib. In fact this is not a good way. It's much better to use RPATH. There is a very useful doc page about it. Check it out. Well if you write something like this in your top level CMakeLists.txt, it will solve the problem:
SET(CMAKE_SKIP_BUILD_RPATH FALSE)
SET(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib64")
SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib64")
Add the path of the directory containing the library to the LD_LIBRARY_PATH environment variable, by appanding a new path:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/the/library/
You can check the library is correctly found with the 'ldd' tool:
lld ./executable
If the library is not stated as "not found" it is OK and your executable will be executed properly.
Add the 'export' command to your bashrc to properly set the LD_LIBRARY_PATH variable after each system reboot, otherwise you will have to execute again the 'export' command.
I have some 3rd party libraries and includes (I have copied them to the this location /usr/ssd/include and /usr/ssd/lib) that I need to link with my application. I have just created a test application to see if I can link ok. However, when I try to run my app I get the following message.
./app: error while loading shared libraries: libssdn.so: cannot open shared object file: No such file or directory
On the command line I am compiling like this:
gcc -g -Wall -I/usr/ssd/include -L/usr/ssd/lib -lssdn test_app.c -o app
Everything compiles ok, as I don't get any warnings or errors. However, I get the error when I try and run the app.
In the usr/ssd/lib the library is called libssdn.so
I am been looking for solution and I have read something about -rpath, -Wl and LD_LIBRARY_PATH, but not sure what they are and how to include them when I compile.
I am using Ubuntu 9.04 Linux,
Thanks for any advice,
Test if adding /usr/ssd/lib to your $LD_LIBRARY_PATH helps:
In a shell:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/ssd/lib
If that solves the problem, make it permanent by adding /usr/ssd/lib to /etc/ld.so.conf or by running
ldconfig -n /usr/ssd/lib
My personal preference is not to bake the location of a shared object into an executable (which is what -rpath would do).
Instead, you should add /usr/ssd/lib to your LD_LIBRARY_PATH at run time. Assuming you are running bash or a bash like shell, do:
export LD_LIBRARY_PATH=/usr/ssd/lib:${LD_LIBRARY_PATH}
and once you do that, you can run your executable.