How to use __extension__ and __typeof__ in a mini example in C?

Question

I saw that there are such tokens in the gcc source code,

but how to use these 2 tokens?

Answer 1

__ __ extensions:

GCC uses the __extension__ attribute when using the -ansi flag to avoid a warning in headers with GCC extensions. This is mainly used in glibc with a function declaration with a long long

__ __ TypeOf:

MIN and MAX in C are a good example of how it is used. This basically allows you to declare a variable that is of the same type as another variable.