Can Go Safely Return Pointers to Stack-Allocated Variables?

Returning Pointers on the Stack in Go

In C, returning a pointer to a stack-created variable from a function can lead to problems as the memory may be discarded after the function returns, invalidating the pointer. However, in Go, the behavior is different.

In Go, a pointer to a stack-created variable can be safely returned from a function, as the Go compiler uses escape analysis to determine if values pointed to by variables may be used after the function returns. If the compiler cannot prove that the variable is not referenced after the function returns, it will automatically allocate the variable on the garbage-collected heap to avoid dangling pointer errors.

This optimization can be observed using the -gcflags -m option during compilation. Here's an example:

package main

import (
    "fmt"
)

func main() {
    fmt.Println(*(something()))
}

func something() *string {
    s := "a"
    return &s
}

Running this code will print "a", demonstrating that it is safe to return a pointer to a stack-created variable in Go.

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