How to raise warning if return value is disregarded?

Question

I\'d like to see all the places in my code (C++) which disregard return value of a function. How can I do it - with gcc or static code analysis tool?

Bad code exampl

Answer 1

As far as I'm aware there is no GCC option to give this warning. However, if you are interested in specific functions, you can tag them with an attribute:

int fn() __attribute__((warn_unused_result));

which would give a warning if the return value of fn() was not used. Caveat: I've never used this feature myself.