| # - Try to find how to link to the standard math library, if anything at all is needed to do. |

| # On most platforms this is automatic, but for example it's not automatic on QNX. |

| # |

| # Once done this will define |

| # |

| # STANDARD_MATH_LIBRARY_FOUND - we found how to successfully link to the standard math library |

| # STANDARD_MATH_LIBRARY - the name of the standard library that one has to link to. |

| # -- this will be left empty if it's automatic (most platforms). |

| # -- this will be set to "m" on platforms where one must explicitly |

| # pass the "-lm" linker flag. |

| # |

| # Copyright (c) 2010 Benoit Jacob <jacob.benoit.1@gmail.com> |

| # Redistribution and use is allowed according to the terms of the 2-clause BSD license. |

| |

| |

| include(CheckCXXSourceCompiles) |

| |

| # a little test program for c++ math functions. |

| # notice the std:: is required on some platforms such as QNX |

| |

| set(find_standard_math_library_test_program |

| "#include<cmath> |

| int main() { std::sin(0.0); std::log(0.0f); }") |

| |

| # first try compiling/linking the test program without any linker flags |

| |

| set(CMAKE_REQUIRED_FLAGS "") |

| set(CMAKE_REQUIRED_LIBRARIES "") |

| CHECK_CXX_SOURCE_COMPILES( |

| "${find_standard_math_library_test_program}" |

| standard_math_library_linked_to_automatically |

| ) |

| |

| if(standard_math_library_linked_to_automatically) |

| |

| # the test program linked successfully without any linker flag. |

| set(STANDARD_MATH_LIBRARY "") |

| set(STANDARD_MATH_LIBRARY_FOUND TRUE) |

| |

| else() |

| |

| # the test program did not link successfully without any linker flag. |

| # This is a very uncommon case that so far we only saw on QNX. The next try is the |

| # standard name 'm' for the standard math library. |

| |

| set(CMAKE_REQUIRED_LIBRARIES "m") |

| CHECK_CXX_SOURCE_COMPILES( |

| "${find_standard_math_library_test_program}" |

| standard_math_library_linked_to_as_m) |

| |

| if(standard_math_library_linked_to_as_m) |

| |

| # the test program linked successfully when linking to the 'm' library |

| set(STANDARD_MATH_LIBRARY "m") |

| set(STANDARD_MATH_LIBRARY_FOUND TRUE) |

| |

| else() |

| |

| # the test program still doesn't link successfully |

| set(STANDARD_MATH_LIBRARY_FOUND FALSE) |

| |

| endif() |

| |

| endif() |