Compiling C++-code without a file

Question

I\'m trying to compile some C++ code using your standard g++ compiler. However, rather than compiling from a file:

main.cpp:

#include 

        

Answer 1

echo "int main(){}" | gcc -Wall -o testbinary -xc++ -

works but I would like to know how it works and better yet, if there is a way to do this without the need to pipe the contents.

Alternatively you can say (e.g. in a shell-script):

gcc -Wall -o testbinary -xc++ - << EOF
int main(){}
EOF