The concept of “local state cannot be unlocked by another process” refers to the idea that data stored in the local state of a process or function cannot be accessed or modified by any other process or function in a concurrent or parallel computing environment.
In concurrent programming, multiple processes or threads can be executed simultaneously, and each may have its own state or set of data. The local state, also known as local variables or stack variables, is specific to a particular process or thread and resides in its own stack memory.
The local state is typically not shared between processes or threads and is only accessible within the context of the executing process or thread. This is done to ensure data integrity and avoid race conditions or conflicts that may arise when multiple processes or threads try to modify the same data simultaneously.
Example
Let’s consider a simple example in JavaScript to understand this concept better. We have two functions, increment and display, sharing a common local variable count.
function increment() {
let count = 0;
count++;
}
function display() {
console.log(count);
}
increment();
display();
If this code is executed, it will result in an error because the local variable count is restricted to the scope of the increment function only. The display function cannot access or modify the count variable since it exists within the local state of the increment function.
This encapsulation of local state helps prevent unintended interference or race conditions when multiple processes or threads are concurrently accessing and modifying data.