How to understand this trivial declaration in C++?

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C++11

I ran into an example in my study on C++. A trivial case it seems like, but I am interested to know the internal of it:

//Example 1.
//this is easy to understand

int i =100; //a file scope variable

void foo()
{
   int j = i; //j is a automatic variable here
}

my question is the example 2 here

//Example 2
//how to understand this var j declaration works?
int i =100; //file scope variable
int j = i;  //how this var j works internally?

the paper I read explains how var j is assigned to var i as below:

//i =100 is evaluated in runtime, not compile time
//compiler generated initialization function
_sti_i_foo_c(){ j = i ;}

MY question is: how can I know this kind of internals such this function _sti_i_foo_c() generated.

I ask this question here to seek more insights from gurus in this community.

thank you!

What I have tried:

I do not have a good idea on how this _sti_i_foo_c() function is generated:
use what kind of tool? so that I can find such details?