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Eigen3/demos/mix_eigen_and_c/README

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+This is an example of how one can wrap some of Eigen into a C library.
+
+To try this with GCC, do:
+
+  g++ -c binary_library.cpp -O2 -msse2 -I ../..
+  gcc example.c binary_library.o -o example -lstdc++
+  ./example
+
+TODO: add CMakeLists, add more explanations here