cmake/Help/guide/tutorial/Step7/MathFunctions/CMakeLists.txt

add_library(MathFunctions MathFunctions.cxx)

# state that anybody linking to us needs to include the current source dir
# to find MathFunctions.h, while we don't.
target_include_directories(MathFunctions
                           INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
                           )

# should we use our own math functions
option(USE_MYMATH "Use tutorial provided math implementation" ON)
if (USE_MYMATH)
  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")

  # library that just does sqrt
  add_library(SqrtLibrary STATIC
              mysqrt.cxx
              )

  # link SqrtLibrary to tutorial_compiler_flags
  target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)

  # TODO 1: Include CheckCXXSourceCompiles

  # TODO 2: Use check_cxx_source_compiles with simple C++ code to verify
  # availability of:
  # * std::log
  # * std::exp
  # Store the results in HAVE_LOG and HAVE_EXP respectively.

  # Hint: Sample C++ code which uses log:
  # #include <cmath>
  # int main() {
  #   std::log(1.0);
  #   return 0;
  # }

  # TODO 3: Conditionally on HAVE_LOG and HAVE_EXP, add private compile
  # definitions "HAVE_LOG" and "HAVE_EXP" to the SqrtLibrary target.

  # Hint: Use target_compile_definitions()

  target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
endif()

# link MathFunctions to tutorial_compiler_flags
target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags)

# install libs
set(installable_libs MathFunctions tutorial_compiler_flags)
if(TARGET SqrtLibrary)
  list(APPEND installable_libs SqrtLibrary)
endif()
install(TARGETS ${installable_libs} DESTINATION lib)
# install include headers
install(FILES MathFunctions.h DESTINATION include)