| // run |
| |
| // Copyright 2020 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| //go:build cgo |
| |
| package main |
| |
| import ( |
| "runtime/cgo" |
| "unsafe" |
| ) |
| |
| type S struct { |
| _ cgo.Incomplete |
| x int |
| } |
| |
| func main() { |
| var i int |
| p := (*S)(unsafe.Pointer(uintptr(unsafe.Pointer(&i)))) |
| v := uintptr(unsafe.Pointer(p)) |
| // p is a pointer to a not-in-heap type. Like some C libraries, |
| // we stored an integer in that pointer. That integer just happens |
| // to be the address of i. |
| // v is also the address of i. |
| // p has a base type which is marked not-in-heap, so it |
| // should not be adjusted when the stack is copied. |
| recurse(100, p, v) |
| } |
| func recurse(n int, p *S, v uintptr) { |
| if n > 0 { |
| recurse(n-1, p, v) |
| } |
| if uintptr(unsafe.Pointer(p)) != v { |
| panic("adjusted notinheap pointer") |
| } |
| } |
