upstream/asio/CMakeLists.txt

# Copyright (c) 2016, Intel Corporation
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add_library(asio INTERFACE)

if (NETWORKING)
    # Find ASIO (the standalone version, not Boost) If asio isn't installed in
    # a standard directory, add the correct directory to CMAKE_PREFIX_PATH (see
    # the main README for more information).
    find_path(ASIO_DIR NAMES asio.hpp)
    # Hide this variable from CMake GUIs and `cmake -L`
    set_property(CACHE ASIO_DIR PROPERTY ADVANCED TRUE)
    if (NOT ASIO_DIR)
        message(SEND_ERROR
    " ASIO header (asio.hpp) could not be found.
    ASIO is used for networking. On Linux, you should install it using your
    package manager. On Windows, please refer to the main README.")
    endif()

    # Ubuntu 14.04 packages asio 1.10.1 and clang 3.4.1.
    # In this environment, asio stand alone (set ASIO_STANDALONE)
    # does not correcly detect that the stl has CHRONO support (c++11).
    # Force the use of std::chrono by setting ASIO_HAS_STD_CHRONO
    target_include_directories(asio SYSTEM INTERFACE "${ASIO_DIR}")
    target_link_libraries(asio INTERFACE "${CMAKE_THREAD_LIBS_INIT}")
    target_compile_definitions(asio
                               INTERFACE ASIO_STANDALONE
                               INTERFACE ASIO_HAS_STD_CHRONO)
else()
    # Stubbed version
    target_include_directories(asio INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/stub")
endif()