title: Including gtest libraries in Makefiles for unit test files:
body: <p>I am currently learning how to make and use MakeFiles for programs in C++. I have been able to create and run Makefiles for normal .cpp classes but I am having a problem with test classes. For testing I am using Gtest in Code::Blocks, and in my Test_A.cpp file in the "Linker Settings" I add: </p>
  
  <pre><code> /usr/lib/libgtest.a
   /usr/lib/libgtest_main.a
  </code></pre>
  
  <p>and for the other linker options I put "-pthread". I know that in some way those libraries need to be added in the makefile, but I cannot figure how. I originally thought they need to be added in line 3, but everything I try returns thousands of lines of error of type:</p>
  
  <pre><code> undefined reference to `testing::Test::TearDown()
   undefined reference to `testing::Test::~Test()  etc....
  </code></pre>
  
  <p>My makefile:</p>
  
  <pre><code>1. all: Test
  
  2. Test_A.o: Test_A B.h
  3.      g++ -c Test_A.cpp -o Test_A.o
  
  4. Test: Test_A.o
  5.      g++ -o Test Test_A.o
  
  6. clean:
  7.      rm -rf *o *~
  </code></pre>