How is memory allocated in Golang? What is from the heap, and what is from the stack?

In Go, memory is allocated automatically, but conceptually there is a stack and a heap.

• Stack is used for local variables of functions and parameters. It is quickly allocated and freed when calling and returning from functions.
• Heap is used for objects that need to live longer than the function call, for example, if a variable is returned from a function or its address is stored outside the function.

The Go compiler and garbage collector decide where to place a variable (escape analysis). If a variable "escapes" from the stack (for example, its address is passed outside), it is placed on the heap.

Example:

func foo() *int {
    x := 10 // local variable
    return &x // x "escapes" to the heap
}

func main() {
    p := foo() // p points to the heap
    fmt.Println(*p)
}

Here, x will be placed on the heap because its address is returned from the function.