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go/test/nilptr/arrayindex.go
Rob Pike 4f61fc96b2 test: remove semiocolons.
The ken directory is untouched so we have some examples with explicit semis.

R=gri
CC=golang-dev
https://golang.org/cl/2157041
2010-09-04 10:36:13 +10:00

28 lines
789 B
Go

// [ $GOOS != nacl ] || exit 0 # do not bother on NaCl
// $G $D/$F.go && $L $F.$A &&
// ((! sh -c ./$A.out) >/dev/null 2>&1 || echo BUG: should fail)
// Copyright 2009 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.
package main
import "unsafe"
var x byte
func main() {
var p *[1<<30]byte = nil
x = 123
// The problem here is not the use of unsafe:
// it is that indexing into p[] with a large
// enough index jumps out of the unmapped section
// at the beginning of memory and into valid memory.
// Pointer offsets and array indices, if they are
// very large, need to dereference the base pointer
// to trigger a trap.
println(p[uintptr(unsafe.Pointer(&x))]) // should crash
}