DeVault: Announcing the Hare programming language

> In practice I *know* that dereferencing a NULL on any modern platform causes a SEGV and I'm using it exactly for that purpose.

That depends on what you consider a modern platform - there are ARMv8-M microcontrollers where address 0 is the start of flash, and reading NULL will return some non-zero data (because that's where the vector table is stored). (Writing to NULL might raise an exception or actually modify flash, depending on the current configuration of the flash controller.)

> Except that my code was there precisely to provoke a panic and crash the program before it degenerates

If you're explicitly writing to NULL, Clang will optimise it away but helpfully tells you:

> warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
> *(int *)0 = 0;
> ^~~~~~~~~
> note: consider using __builtin_trap() or qualifying pointer with 'volatile'

volatile prevents the optimisation, so it will emit the write instruction. __builtin_trap typically emits an undefined instruction (ud2 on x86), which will crash even on systems where 0 is a valid address.