On Sat, Sep 7, 2013 at 12:09 PM, Oren Ben-Kiki <o...@ben-kiki.org> wrote:
> If in practice on any machine today (X86, ARM, PowerPC, MIPS, SPARC, ...) > every null pointer will fault (which I strongly hope will...), then I'd be > quite happy in saying formally that accessing a hole leads to "undefined > behavior" and make good use of knowledge that any such access will, in > fact, fault, on any machine I might be coding to today. > You get a segmentation fault on Linux because the first page is marked read-only for userland processes. It's valid on almost any hardware to dereference a pointer equal to zero, which is how LLVM defines the null pointer. However, LLVM explicitly considers a dereference of the null pointer to be undefined behaviour so it doesn't matter how it could or couldn't be implemented in hardware.
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