multithreading - Simple background process question in bash

Question

I am using BASH and I am calling a couple of functions which update a couple of variables. These functions take too long to complete so I was thinking running all of the functions in the background so that they can be running simultaneously. This is a basic example of what i am asking.

#/bin/bash

func1()
{
    var1="one"

}

func2()
{
    var2="two"

}

func3()
{
    var3="three"

}

echo "Right now this is what i am doing"
func1 &
func2 &
func3 &
wait
echo "The variables are $var1 $var2 $var3"
echo "But the variables are empty. 
echo "Hence, I am assuming that they are not accessible outside of the function"

I feel like I am missing something very silly. Of course if I don't run the functions in the background, they show the correct variables. Thank you in advance.

Answer 1

If you run something in the background, it runs as a separate child process, with its own environment.

It cannot affect the environment of the current process (the parent process of those subshells).

So it's not so much that the variables aren't available outside of the function as they're not available outside of the process. The function is irrelevant since, if you run them in the foreground (without the &), the variables are set just fine.