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5c84eca210
Since commit 07223c5c27 (Tutorial: Update Step 5 to work on Windows,
2020-02-18, v3.18.0-rc1~655^2) the logic does not work on non-Windows
platforms when cmake is re-run on an existing build tree. It is also
more complicated than we'd like for a tutorial example. Avoid the need
to consider the `m` library case by performing the check as C++.
Since `check_cxx_symbol_exists` cannot handle overloaded functions
like `exp` and `log`, check with `check_cxx_source_compiles` instead.
This also presents a more general-purpose example in the tutorial.
Fixes: #23524
35 lines
846 B
CMake
35 lines
846 B
CMake
add_library(MathFunctions mysqrt.cxx)
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# state that anybody linking to us needs to include the current source dir
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# to find MathFunctions.h, while we don't.
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target_include_directories(MathFunctions
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INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
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)
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# does this system provide the log and exp functions?
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include(CheckCXXSourceCompiles)
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check_cxx_source_compiles("
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#include <cmath>
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int main() {
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std::log(1.0);
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return 0;
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}
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" HAVE_LOG)
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check_cxx_source_compiles("
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#include <cmath>
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int main() {
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std::exp(1.0);
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return 0;
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}
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" HAVE_EXP)
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# add compile definitions
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if(HAVE_LOG AND HAVE_EXP)
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target_compile_definitions(MathFunctions
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PRIVATE "HAVE_LOG" "HAVE_EXP")
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endif()
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# install rules
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install(TARGETS MathFunctions DESTINATION lib)
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install(FILES MathFunctions.h DESTINATION include)
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