Try this in C: \*(int\*)0 = 0; Modern C compilers could require you to complicat...

DannyBee · 2025-08-27T19:28:11 1756322891

Unless you were on systems that mapped address 0 to a writable but always zero value so they could do load and store speculation without worry.

IBM did this for a long time

mabster · 2025-08-27T22:07:21 1756332441

My favourite were older embedded systems where 0 was an address you actually do interact with. So for some portion of the code you WANT null pointer access. I can't remember the details but I do remember jumping to null to reset the system being pretty common.

marshray · 2025-08-27T22:23:46 1756333426

Probably the system interrupt table. Index 0 might reference the handler for the non-maskable interrupt NMI, often the same as a power-on reset.

I recall that on DOS, Borland Turbo C would detect writes to address 0 and print a message during normal program exit.

ghurtado · 2025-08-28T07:01:35 1756364495

RANDOMIZE USR 0

ncruces · 2025-08-28T13:31:32 1756387892

In Wasm you can read/write whatever to address zero of linear memory.

It's still UB as far as clang is concerned so you C code can do whatever. But it won't “crash” on the spot.