I have a library in: C:\vcpkg\installer\x86-windows-static\lib and I would like to link it via this absolute path.
The cmake file resides elsewhere, it is for an executable program (not a library).
Is it possible to link for example example_lib.lib from this absolute path?
Everywhere I read it's just about building the library, but I just want to link on it, .lib specifically.
The CMakes target_link_libraries() allows you to specify the library via an absolute path.
Related
I working on a C++ application running on Linux. The project uses CMake.
It use a third party shared library. Unfortunately, the third party library doesn't end with .so.
And the CMake command find_library can't find the library.
Does anyone now how to force CMake to find libraries with a custom file extension? Or at least, how to configure GCC (through CMake) for linking with the library ending with a custom extension?
Thanks for any hint!
You can set the CMAKE_FIND_LIBRARY_SUFFIXES variable. From the documentation:
This specifies what suffixes to add to library names when the
find_library() command looks for libraries. On Windows systems this is
typically .lib and .dll, meaning that when trying to find the foo
library it will look for foo.dll etc.
Adding the custom suffix to it should do the trick.
I have seen several other answers in order to add a library to my C+= project in eclipse.I have tried to add the path to the linker in Miscellaneous section using -L"and the path of the folder" and -l"the name without the lib prefix in the begging and the .so at the end"
I try to add libxl library so i use -lxl (for libxl.so) and -L/home/username/libxl3.5.3.0/lib/ (which the location of the lib file).
I have also tried to give it under the Linker menu and adding the name and the path in the Libraries section.
I get error that: /usr/bin/ld does not find -lxl file and it returns error
I am using -static to linker in order to make an executable that has the all the libs included but when i do not use -static the problem with the lib resolves from build but still when i try to run the program i get error that i the program can not open shared file libxl.so cause the file does not exist.How can i fix this?
When you add the library name to a C++ project in eclipse, do not prefix it with -l. Eclipse will do this for you when it invokes the compiler. For example if you want the boost_regex library, just input boost_regex not lboost_regex. Eclipse will do the rest for you. Or in your specific case, just use xl not lxl. You don't need the - either, nor the -L before paths as erenon points out in the comment below. Note that the above applies to the method of adding libraries using the Project->Properties->C/C++ General->Paths and Symbols dialog form for adding libraries using the Libraries and Library Paths tabs.
You are trying to link statically to a shared library. In my experience I have always used *.a files rather than *.so files to employ static linkage. This other answer Static link of shared library function in gcc seems to suggest that you are not actually able to link statically to *.so files.
I've been trying to include different types of libraries with CMake.
.a
.dylib
.so
I finally, got both the .a and .dylib to work with this code.
find_library(libname NAMES libcef.dylib PATHS ${libname_PATH})
along with this, underneath where I add_executable to initialize all my files for the build.
target_link_libraries(${PROJECT_NAME} ${libname})
However, I tried using the same code on a .so file and it doesn't seem to work.
I get this statement from cmake when I try building.
Target "project name" links to item
-- path of file --
which is a full-path but not a valid library file name.
I'm not sure if this is the correct way to handle .so files or perhaps I'm not even fully understanding what an .so file is. Any input and/or clarification would be much appreciated.
edit:
THEORY- my theory is because it doesn't have a lib in front of the name of the library name its called ffmpegsumo.so. However, when i try renaming it the file name still saves into the variable name very strange.
The same should work with .so files also, just make sure the required .so file is present at ${libname_PATH} which you have given.
find_library treats all types (.a / .so/ .dylib/ .dll) the same way. Problem may be the following
-- path not set up correctly
-- error because of absolute path
-- .so not present
-- If the error is from build (not from configure only) the .so might be corrupt, try replacing it
--Your library does not seem to be valid
Shared libraries are linked dynamically. That means that your OS will automatically look for and load the .so files when the time comes to run the application. You only need to tell cmake the name of the library and the OS will take care of the rest.
For example, if you want to link to the dynamic library for libSDL.so, you just say: target_link_libraries(${PROJECT_NAME} SDL)
As a sanity check, your linker will look to make sure that the SDL library does exist on your computer. That's why you might get a linking error if that library is not available at link-time, even if it's really a dynamic library.
I have been trying to compile TinyXML using CMake as a sort of mini project, trying to learn CMake. As an addition I am trying to make it compile into a dynamic library and install itself so it works.
So far I have managed to get it to compile and install BUT it compiles into a .dll and a .dll.a and the only way to get it to work is to have it install into both /bin and /lib, which makes it install both files in both folders. This setup works but I'm guessing the .dll should be in /bin and the .dll.a should be in /lib. Is this some sort of Cygwin-specific problem or am I doing something wrong?
The .dll is the runtime library file, which must be present on the target system on run time (and be in $PATH there). The .dll.a file is the import library for the .dll, which must be present on the compiling machine at link time. You need to distribute the .dll file to the places where the program should run, and both .dll and .dll.a to places where the library is used to link other programs. you don't need the .dll.a file on the machines running the program only.
When you don't want to create a shared library, you can tell this to cmake with the static keyword in the add_library command:
add_library(mylib STATIC foo.c bar.cpp)
This way there will no shared library created, but the code from the library will be added by the linker into the final executable file.
What you need is to specify a destination for each type of file.
The .dll is considered a RUNTIME library and the .a is an ARCHIVE. Just in case, for other platforms, you probably want the LIBRARY entry (for .so files).
install( TARGETS ${PROJECT_NAME}
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib
RUNTIME DESTINATION bin
)
I pulled out an application that I wrote in C++ using the sfml library, but I'm having trouble setting up the library in Eclipse. I specified the include path, the lib path and included all the necessary .so libraries to link to. the application compiles fine but it complains at runtime about missing libraries. Why is this happening? Didn't I include the path to the libraries in the project settings already? I have even tried to place all the .so's in the executable directory with no luck.
There is only the name of the shared lib stored in the executable. At program startup the dynamic linker then searches for the specified libs in its search paths. You can add/specify search paths by placing them colon separated in the environment variable LD_LIBRARY_PATH or by specifying them in /etc/ld.so.conf (at least if you use some unix based OS). On windows the whole PATH environment variable is used when searching for dynamic-link libraries (DLL).
To see the paths of shared libraries used by a given application run ldd applicationPath.