包括共享库（.so）和CMake

Question

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.

Answer 1

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

Answer 2

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.