[136] | 1 | # - Try to find how to link to the standard math library, if anything at all is needed to do.
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| 2 | # On most platforms this is automatic, but for example it's not automatic on QNX.
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| 3 | #
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| 4 | # Once done this will define
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| 5 | #
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| 6 | # STANDARD_MATH_LIBRARY_FOUND - we found how to successfully link to the standard math library
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| 7 | # STANDARD_MATH_LIBRARY - the name of the standard library that one has to link to.
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| 8 | # -- this will be left empty if it's automatic (most platforms).
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| 9 | # -- this will be set to "m" on platforms where one must explicitly
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| 10 | # pass the "-lm" linker flag.
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| 11 | #
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| 12 | # Copyright (c) 2010 Benoit Jacob <jacob.benoit.1@gmail.com>
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| 13 | # Redistribution and use is allowed according to the terms of the 2-clause BSD license.
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| 14 |
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| 15 |
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| 16 | include(CheckCXXSourceCompiles)
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| 17 |
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| 18 | # a little test program for c++ math functions.
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| 19 | # notice the std:: is required on some platforms such as QNX
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| 20 |
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| 21 | set(find_standard_math_library_test_program
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| 22 | "#include<cmath>
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| 23 | int main() { std::sin(0.0); std::log(0.0f); }")
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| 24 |
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| 25 | # first try compiling/linking the test program without any linker flags
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| 26 |
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| 27 | set(CMAKE_REQUIRED_FLAGS "")
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| 28 | set(CMAKE_REQUIRED_LIBRARIES "")
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| 29 | CHECK_CXX_SOURCE_COMPILES(
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| 30 | "${find_standard_math_library_test_program}"
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| 31 | standard_math_library_linked_to_automatically
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| 32 | )
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| 33 |
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| 34 | if(standard_math_library_linked_to_automatically)
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| 35 |
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| 36 | # the test program linked successfully without any linker flag.
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| 37 | set(STANDARD_MATH_LIBRARY "")
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| 38 | set(STANDARD_MATH_LIBRARY_FOUND TRUE)
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| 39 |
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| 40 | else()
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| 41 |
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| 42 | # the test program did not link successfully without any linker flag.
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| 43 | # This is a very uncommon case that so far we only saw on QNX. The next try is the
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| 44 | # standard name 'm' for the standard math library.
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| 45 |
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| 46 | set(CMAKE_REQUIRED_LIBRARIES "m")
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| 47 | CHECK_CXX_SOURCE_COMPILES(
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| 48 | "${find_standard_math_library_test_program}"
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| 49 | standard_math_library_linked_to_as_m)
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| 50 |
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| 51 | if(standard_math_library_linked_to_as_m)
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| 52 |
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| 53 | # the test program linked successfully when linking to the 'm' library
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| 54 | set(STANDARD_MATH_LIBRARY "m")
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| 55 | set(STANDARD_MATH_LIBRARY_FOUND TRUE)
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| 56 |
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| 57 | else()
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| 58 |
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| 59 | # the test program still doesn't link successfully
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| 60 | set(STANDARD_MATH_LIBRARY_FOUND FALSE)
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| 61 |
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| 62 | endif()
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| 63 |
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| 64 | endif()
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