multiple definition of `main' if using precompiled googletest library (no cmake)

[anb0s]

I'm facing linker error when using with already created googletest library:

Linking D:\git\s7p\work3\s7p.base/bin/unittest/vdk_signals_tests/vdk_signals_tests.o...
d:/git/s7p/work3/s7p.tools/win64_gcc_mingw64_9.2.0/bin/../lib/gcc/x86_64-w64-mingw32/9.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: D:\git\s7p\work3\s7p.base\obj\unittest\base\user\googletest.o: in function `main':
D:/git/s7p/work3/s7p.base/google/test-master/googlemock/src/gmock_main.cc:56: multiple definition of `main'; D:\git\s7p\work3\s7p.base\obj\unittest\user\vdk_signals_tests.o:D:/git/s7p/work3/s7p.base/vdk/signals-master/tests/tests.cpp:948: first defined here
collect2.exe: error: ld returned 1 exit status

I'm not using cmake and therefore the problem belongs to my environment with prcompiled googletest library with main. May be an #if defined(VDK_SIGNALS_USE_OWN_MAIN) can be used to configure this from users perspective? Thanks!

[vdksoft]

I don’t quite understand this issue. If you don’t use cmake, then you compile it without using a build tool. In this case, cmake does not download google test (since there is no cmake), and I don’t understand why you have multiple definitions of main (where the second main comes from?).

[anb0s]

The file tests.cpp defines the test cases and the main function:

int main(int argc, char ** argv)
{
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

If i compile the vdk tests and link them with own googletest build and own main() function with extensions etc. then the main function is defined twice and it cannot be linked.

From my point of view the main function should be opt-in e.g. in another file file test_main.cpp (will skip via build system if not needed) or via preprocessor:

#if defined(VDK_SIGNALS_USE_MAIN)
int main(int argc, char ** argv)
{
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}
#endif

[anb0s]

or opt-out:

#if !defined(VDK_SIGNALS_DONOT_USE_MAIN)
int main(int argc, char ** argv)
{
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}
#endif

The user can then add -DVDK_SIGNALS_DONOT_USE_MAIN to disable vdk-test-main and link own main.