Under what conditions does automatic memory allocation from the dynamic area occur during compilation or program execution?

In Go, automatic memory allocation from the dynamic area (heap) occurs during program execution when the compiler or runtime determines that a variable should live longer than the current function or goroutine.

Conditions under which allocation occurs on the heap:

• If a variable is captured by a closure and can be used after the function exits.
• If a variable is returned from a function or passed to another goroutine.
• If the compiler cannot guarantee that the variable will be destroyed after exiting the current scope.

The Go compiler performs escape analysis to determine which variables need to be allocated on the heap and which on the stack.

Example:

func f() *int {
    x := 10
    return &x // x "escapes" to the heap because its pointer is returned
}

Here, x is allocated on the heap because a pointer to it is returned from the function and can be used outside its scope.