Question

I’ve compiled Google C++ Test. I’m now trying to add it to my g++ installation (on Cygwin) such that I don’t have to specify -I, -L, and -l for every project. The steps I did were:

1. I put a symlink in /usr/local/include to GTEST_ROOT/include/gtest
2. I put symlinks in /usr/local/lib to the libs in GTEST_ROOT/lib (libgtest.la libgtest_main.la)
3. I wrote a proof program to test the setup

The test program compiles fine with g++ -c proof.cpp but g++ proof.cpp gives errors during the linking, saying that the gtest references can’t be found.

Using grep to search my GTEST_ROOT for the required references, I found them in additional libs in GTEST_ROOT/lib/.libs (libgtest.a libgtest.la libgtest.lai libgtest_main.a libgtest_main.la libgtest_main.lai)

Due to time constraints, I got it to work using the following command g++ -LGTEST_ROOT/lib/.libs -lgtest proof.cpp and I’ve put this in a makefile.

However, I’m still trying to get my setup such that g++ proof.cpp would just work. What am I missing?

Thanks to Matt, I understand now that I cannot drop the -lgtest. I would like to at least get rid of the -LGTEST_ROOT/lib/.libs. I’ve added symlinks to the additional .a and .lai files provided. However, g++ proof.cpp -lgtest now gives me the linker error: cannot find -lgtest

NOTE: symlinking the libs in GTEST_ROOT/lib/.libs still does not give the desired results.

Answer 1

You’ll always need to pass -lgtest to your final compile/link step¹. GCC will not search all the libraries in its search path for the symbols that it is missing (that would be way too expensive).

The library files themselves (.so or .a) need to be in the /usr/local/lib/ directory, or a symlink to those files. Symlinking a directory there will not work.

¹_{well, that’s not technically true. You could modify your spec file, but don’t do that.}