Squashed 'third_party/eigen/' content from commit 61d72f6
Change-Id: Iccc90fa0b55ab44037f018046d2fcffd90d9d025
git-subtree-dir: third_party/eigen
git-subtree-split: 61d72f6383cfa842868c53e30e087b0258177257
diff --git a/cmake/FindStandardMathLibrary.cmake b/cmake/FindStandardMathLibrary.cmake
new file mode 100644
index 0000000..711b0e4
--- /dev/null
+++ b/cmake/FindStandardMathLibrary.cmake
@@ -0,0 +1,64 @@
+# - 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()