Why does a “function name” evaluate to true in C and how to get warned on it

Question

I recently stumbled across the following behaviour of gcc 3.2.2 writing a c program:

In an if statement I forgot the braces of a function and wrote:

if

Answer 1

Pointers to functions are sometimes useful - as callbacks eg in sort routines or data capture. Or for doing optimized calculated-goto type routines, since C doesn't have templates.

But 99% of the time it's an error, newer compilers will warn you