How Does Go Handle Returning Pointers to Local Structs?

Return Pointer to Local Struct in Go

In Go, constructs such as this are used to create and return a pointer to a local struct:

type point struct {
  x, y int
}

func newPoint() *point {
  return &point{10, 20}
}

While this may seem like an erroneous practice in C , the semantics in Go are different.

Pointer Escape Analysis and Memory Allocation

Go employs pointer escape analysis to determine whether a pointer escapes the local stack scope. In the example above, the pointer returned by newPoint() indeed escapes the local function. As a result, the object is allocated on the heap.

However, if the pointer were to remain within the scope of the function (i.e., it does not escape), the compiler has the freedom to allocate the object on the stack. However, it's important to note that this is not guaranteed by the compiler.

Therefore, the memory allocation depends on whether the pointer escape analysis can unequivocally conclude that the pointer remains local to the function. In cases where the pointer does escape, such as in the example provided, the object is allocated on the heap.

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