What does this line mean in C/C++?

Question

C++ / C#

double (*func)(double x);- this variable stores the address of the function loaded from the *.so library. For me, such designs are still complicated. I guess this is an abbreviated record (probably). If so, what would the full record look like.

Answer 1

No, that's the full notation, a variable called func that holds a pointer to a function that takes a double and returns a double.
Read in a spiral: https://habr.com/en/post/100104/
If possible, it's better to use std::function - it's more readable
https://en.cppreference.com/w/cpp/utility/function.. .