When Does Go Allocate Heap Memory for Structs Returned by Pointer?: A Deep Dive into Pointer Escape Analysis

Return Pointer to Local Struct: Understanding Pointer Escape Analysis

In Go, the concept of returning pointers to local structs may raise questions for developers with a C background. It deviates from the traditional understanding of memory management in C . In this article, we explore the semantics behind such constructs and clarify where the new point is allocated.

The code sample in question creates a struct named point and a function newPoint that returns a pointer to a point struct. The function initializes the struct with specific values of 10 and 20.

In C , returning a pointer to a local variable is not allowed, as the memory associated with the variable is destroyed when the function returns. However, in Go, pointer escape analysis plays a crucial role.

Pointer escape analysis is a compiler optimization technique that determines whether a pointer escaping its local scope can be reallocated on the heap. In this case, since the pointer to the point struct is returned from the function, it is considered to have escaped the local scope. Therefore, the compiler allocates the struct on the heap.

It's important to note that the compiler's pointer escape analysis is not always perfect. There are scenarios where a pointer may escape the local scope but the compiler conservatively chooses not to allocate it on the heap. In such cases, the object may be allocated on the stack. However, the compiler provides no guarantees in such situations.

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