Gtest: test compiling error - c++

Question

I'm trying to test a motor control lib I've wrote with googletest but I'm not been to compile the test's codes.
The test are in a file named test.cpp such as the following:
#include <gtest/gtest.h>
#include "../motor.hpp"
TEST(constructorTest, contructorDefault)
{
}
And I've put a the tests main function in an other file named main.cpp.
#include <gtest/gtest.h>
#include "../motor.hpp"
int main(int argc, char* argv[])
{
::testing::InitGoogleTest(&argc,argv);
RUN_ALL_TESTS();
}
To compile I've excecuted the following line:
g++ main.cpp test.cpp ../motor.cpp -o test
The result I get is:
main.cpp:8:17: warning: ignoring return value of ‘int RUN_ALL_TESTS()’, declared with attribute warn_unused_result [-Wunused-result]
RUN_ALL_TESTS();
^
/tmp/ccZ5BaBH.o: In function `main':
main.cpp:(.text+0x1e): undefined reference to `testing::InitGoogleTest(int*, char**)'
/tmp/ccZ5BaBH.o: In function `RUN_ALL_TESTS()':
main.cpp:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0x5): undefined reference to `testing::UnitTest::GetInstance()'
main.cpp:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0xd): undefined reference to `testing::UnitTest::Run()'
/tmp/ccFuAMp3.o: In function `__static_initialization_and_destruction_0(int, int)':
test.cpp:(.text+0x5c): undefined reference to `testing::internal::GetTestTypeId()'
test.cpp:(.text+0x84): undefined reference to `testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)'
/tmp/ccFuAMp3.o: In function `constructorTest_contructorDefault_Test::constructorTest_contructorDefault_Test()':
test.cpp:(.text._ZN38constructorTest_contructorDefault_TestC2Ev[_ZN38constructorTest_contructorDefault_TestC5Ev]+0x14): undefined reference to `testing::Test::Test()'
/tmp/ccFuAMp3.o:(.rodata._ZTV38constructorTest_contructorDefault_Test[_ZTV38constructorTest_contructorDefault_Test]+0x20): undefined reference to `testing::Test::SetUp()'
/tmp/ccFuAMp3.o:(.rodata._ZTV38constructorTest_contructorDefault_Test[_ZTV38constructorTest_contructorDefault_Test]+0x28): undefined reference to `testing::Test::TearDown()'
/tmp/ccFuAMp3.o: In function `constructorTest_contructorDefault_Test::~constructorTest_contructorDefault_Test()':
test.cpp:(.text._ZN38constructorTest_contructorDefault_TestD2Ev[_ZN38constructorTest_contructorDefault_TestD5Ev]+0x1f): undefined reference to `testing::Test::~Test()'
/tmp/ccFuAMp3.o:(.rodata._ZTI38constructorTest_contructorDefault_Test[_ZTI38constructorTest_contructorDefault_Test]+0x10): undefined reference to `typeinfo for testing::Test'
collect2: error: ld returned 1 exit status
If I remove the test.cpp of the compiling line I get this other result:
main.cpp: In function ‘int main(int, char**)’:
main.cpp:8:17: warning: ignoring return value of ‘int RUN_ALL_TESTS()’, declared with attribute warn_unused_result [-Wunused-result]
RUN_ALL_TESTS();
^
/tmp/cc61r6NU.o: In function `main':
main.cpp:(.text+0x1e): undefined reference to `testing::InitGoogleTest(int*, char**)'
/tmp/cc61r6NU.o: In function `RUN_ALL_TESTS()':
main.cpp:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0x5): undefined reference to `testing::UnitTest::GetInstance()'
main.cpp:(.text._Z13RUN_ALL_TESTSv[_Z13RUN_ALL_TESTSv]+0xd): undefined reference to `testing::UnitTest::Run()'
collect2: error: ld returned 1 exit status
What am I doing wrong?
EDIT
Look like What #RippeR says is right, but now I getting the following error:
/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../lib/libgtest.so: undefined reference to `pthread_key_create'
/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../lib/libgtest.so: undefined reference to `pthread_getspecific'
/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../lib/libgtest.so: undefined reference to `pthread_key_delete'
/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../lib/libgtest.so: undefined reference to `pthread_setspecific'
Do I have to include something else?
Solution
The problem was solve adding the -lpthread flag to compile the test.

Answer 1

Try:
g++ main.cpp test.cpp ../motor.cpp -o test -lgtest -lpthread
You have to link external libraries you are using. Including headers is not enough (unless library is header-only). If this solutions doesn't work, or you get error about gcc cannot find lgtest or gtest then you need to install it first (see here).
Also, note that RUN_ALL_TESTS(); returns a value, so your main() should look like:
#include <gtest/gtest.h>
#include "../motor.hpp"
int main(int argc, char* argv[])
{
::testing::InitGoogleTest(&argc,argv);
return RUN_ALL_TESTS();
}
I've updated answer (check 2nd line) to cover your next problem. This is same as before, you really should start to FIND answers to your problems instead of just asking and waiting for someone to do all the work for you.