Question

I want to use gtest but execution tells me

./netTest: error while loading shared libraries: libgtest.so.0:
  cannot open shared object file: No such file or directory

1. What are standard paths in that gcc linker looks for libs
2. What is standard path of Debian to store libs
3. How do I add libpaths to g++ (-L flag correct?)

Note on 2: I ask because the libs of gtest are in /usr/local/libs/ but in there is just python and gtest. All other libs are in /usr/lib/. Hence i guess the gtest installer made something wrong.

Answer 1

PS. Perhaps you could just instal the Debian libgtest-dev package (if there’s one).

1. What are standard paths in that gcc linker looks for libs

You can see it with gcc -v -x c /dev/null -o /dev/null 2>&1 | grep LIBRARY_PATH

1. What is standard path of Debian to store libs

Perhaps you meant where the dynamic loader will look for shared libraries.
Check /etc/ld.so.conf and/or files in /etc/ld.so.conf.d/.

1. How do I add libpaths to g++ (-L flag correct?)

You can use the --rpath option to ld. However, I would suggest using it only during development and not in deployment.

You can also set LD_LIBRARY_PATH to the location of your libgtest.so.0.