How can the Intel C++ libraries path be added to the runtime library path using CMake?

Question

I am developing a library using CMake for building automation. I have a problem when using the Intel C++ Compiler. As a matter of fact, the compilation is successful.
However, when I call the library in another project, where the Intel environmental variables are not set, the compilation fails since some Intel C++ internal libraries (e.g., libsycl or libsvml) cannot be found. It seems that Intel internal library directories are not added automatically to the runtime library search path. In order to solve this issue, I had to add to the CMakeList.txt

set_target_properties(myLib PROPERTIES LINK_FLAGS "-Wl,-rpath=${SYCL_LIBRARY_DIR}:${SYCL_LIBRARY_DIR}/../compiler/lib/intel64_lin")

I do not think this is the best way to solve the issue, since it should be modified if the library starts using Intel libraries not contained in those directories and it is platform dependent. How can I solve this problem?

Answer 1

There are multiple questions in this question, the way I read it:

1. How do I make sure my CMake library project exposes all dependencies to the parent project?

2. How do I properly include an external library in a CMake application project?

As for 1., CMake library projects expose multiple levels of sharing, the two most common ones:

• PRIVATE
• PUBLIC

PRIVATE (default usually) means that the configuration is kept library specific, and any dependees on the library don't get access to it, for example private / library-only include paths. You would use PUBLIC to expose any paths that a dependee needs to know:

target_include_directories(myLib 
                       PUBLIC
                       "${CMAKE_CURRENT_SOURCE_DIR}/include/"
)
target_include_directories(myLib 
                       PRIVATE
                       "${CMAKE_CURRENT_SOURCE_DIR}/library-src/"
)

When another project links to this library, it will also have "${CMAKE_CURRENT_SOURCE_DIR}/include/" in its include paths, but not "${CMAKE_CURRENT_SOURCE_DIR}/library-src/".

See https://cmake.org/cmake/help/latest/guide/importing-exporting/index.html

The same can be done for linking options, and other important aspect of your build / publicly exposed interface like headers.

As for question 2., it's important to know the conventions. Usually finding and linking libraries is done with find_library (or any other functions for importing external configuration).

Your library package can require the parent project to expose variables (or options) like $INTEL_LIBRARIES_PATH which you would share across you projects. Configuration would happen during runninng cmake in the uppermost source directory (i.e. pointing to libraries, paths, etc, configurable variables are also possible in CMake, see option).

If the Intel Compiler exposes a library, package or other CMake configuration file you can include in your library when you include it with find_package or find_library, after that it should always be available for the library as long as the machine where it is compiled also has these configurations, compilers and libraries available.

The dependencies guide should give you a good head start for anything not covered here: https://cmake.org/cmake/help/latest/guide/using-dependencies/index.html#guide:Using%20Dependencies%20Guide

The Intel Specific package should be included with:

find_package(IntelDPCPP REQUIRED)

https://www.intel.com/content/www/us/en/docs/dpcpp-cpp-compiler/developer-guide-reference/2023-0/use-cmake-with-the-compiler.html