When your C code just stares into the void pointer abyss

Description

A dark-mode meme shows a Wojak-style line-art figure on the right, sketched in white against a solid black background, with its arm outstretched and index finger pointing left. Floating on the left side is a perfectly round, pitch-black circle that visually represents absolute nothingness. Center-top, rendered in a light-blue monospace font, the exact code snippet "void *empty;" appears, declaring a void pointer named "empty". The joke riffs on low-level C programming: a void* can point to any type yet, if left unassigned, it literally points to the void - invoking memories of null dereferences, undefined behaviour, and manual memory-management dread familiar to systems engineers

Common Tags

CFamilyLanguages PointersInC UndefinedBehavior SegmentationFault ManualMemoryManagement LowLevelProgramming

Comments

Anonymous ★ Top Pick Fifteen architecture reviews later, the “extensible plugin framework” is still a single global void *empty; - apparently undefined behaviour is the most scalable abstraction

Anonymous ★ Top Pick

Fifteen architecture reviews later, the “extensible plugin framework” is still a single global void *empty; - apparently undefined behaviour is the most scalable abstraction
Anonymous

After 20 years in the industry, I've learned that void pointers aren't just type-erased memory addresses - they're portals to the shadow realm where your debugger fears to tread and valgrind whispers 'definitely lost: 8 bytes in 1 blocks'
Anonymous

When you dereference that void pointer at 3 AM and realize you've been staring into the abyss of uninitialized memory - and the abyss segfaults back. The real horror isn't the undefined behavior; it's explaining to the on-call team why production went down because someone thought 'void *empty' was just a philosophical statement, not a ticking time bomb waiting for that inevitable NULL check you forgot to write
Anonymous

Dereference that void*, and the void dereferences your stack trace right back
Anonymous

void* empty; - the event horizon of our ABI where every type crosses and type safety never returns
Anonymous

void* is the black hole of type systems - everything fits until invariants spaghettify into a 3am segfault
Deleted Account 4y

void*
@sylfn 4y

fixed
1. @cptnBoku 4y
  
  Bruh
2. @callofvoid0 4y
  
  exactly me
@AlexKart20129 4y

void *empty=nullptr;
@RiedleroD 4y

recently i had a uint8_t*& and I didn't like it. dereferencing yielded a uint8_t&. Dereferencing twice yielded an exception about how I can't dereference an uint8_t. I'm tired.
1. @sylfn 4y
  
  you cant dereference references, only pointers
  
  @RiedleroD 4y
  
  …why?
  
  @beton_kruglosu_totchno 4y
  
  are you joking?
  
  @RiedleroD 4y
  
  I'm a beginner at C++, give me some slack
  
  @beton_kruglosu_totchno 4y
  
  references are transparent pointers, you do not dereference them, you just use them
  
  @RiedleroD 4y
  
  I didn't even mean to use references. I specifically asked for an uint8_t* to be passed into my function and C++ just gave me an uint8_t*& instead.
  
  @beton_kruglosu_totchno 4y
  
  give us MCVE please :3
  
  @sylfn 4y
  
  references work as pointers but autodereferenced
  
  @RiedleroD 4y
  
  ok so why didn't it let me put a uint8_t& into a function that needed a uint8_t*?
  
  @beton_kruglosu_totchno 4y
  
  because reference is basically same as the value it references
2. @beton_kruglosu_totchno 4y
  
  also, there cannot be a pointer to reference, so you are talking about reference to pointer
  
  @RiedleroD 4y
  
  right, sorry. It was an uint8_t&*.
  
  @RiedleroD 4y
  
  I think.
  
  @sylfn 4y
  
  this is pointer to reference i think, and is disallowed
  
  @beton_kruglosu_totchno 4y
  
  I do not really remember how the types are written so maybe you named it correctly first time I just want to clarify that pointer to references do not exist because reference is supposed to be a compile time abstraction with potentially no runtime storage
  
  @sylfn 4y
  
  but why there is no "array of references"
@SamsonovAnton 4y

int** 0x3f800001 SIGBUS¹ ¹ On architectures that totally disallow unaligned access, like SPARC.
1. @kulikov0 4y
  
  *cpp developer
  
  @sylfn 4y
  
  you can touch yourself!
  
  @kulikov0 4y
  
  Well, I'm in
@hekary715 4y

😳

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When your C code just stares into the void pointer abyss

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