Installing the Google C++ Testing Framework (gtest) globally

Step 1: Change into the temporary directory, for example:

cd /tmp

Step 2: Download the latest (major) version from https://github.com/google/googletest/releases, for example:

wget https://github.com/google/googletest/archive/release-1.10.0.zip

Step 3: Unpack the archive, change to the corresponding directory and build the code from its source (this requires cmake which can be installed using your favorite package manager, for example: apt on Ubuntu or brew on Mac):

unzip release-1.10.0.zip
cd googletest-release-1.10.0/googletest
mkdir bld
cd bld
cmake ..
make

Step 4: Install the files, that is, copy them to the proper systems directories (you need to be root or have sudo rights for that):

cp -a -r ../include/gtest /usr/local/include/.
cp -a ./lib/*.a /usr/local/lib

(optional) Step 5: If the library is (still) not found by the compiler, you can run (as root or with sudo):

ldconfig

(optional) Step 6: Clean up:

cd /tmp
rm -rf release-1.10.0.zip googletest-release-1.10.0

Troubleshooting

Gtest 1.8.1 is the last release supporting pre-C++11 compilers. So if you get any errors when using Gtest > 1.8.1 and a compiler that doesn't use the C++11 standard per default, try to add the -std=c++11 flag to your compile commands, for example:
```
 g++ -std=c++11 -c ApproximateEulersNumber.cpp
```