How does _FORTIFY_SOURCE preprocessor make programs more "secure"

**Channel**

"C++Weekly"

**Topics**

What topics are important to cover for this episode?
- What does it actually do?
- Performance implications
- An example where and why it is beneficial to use `_FORTIFY_SOURCE`

**Length**

Should this be bite-sized (5-10 minutes) or more long form (10-20 minutes)?
I think bite-sized video should cover everything.