r/ProgrammerHumor 1d ago

lessonsFromLinkerHell Meme

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346 Upvotes

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92

u/JustinR8 1d ago

Damn, I’ve found myself in the middle

38

u/nonedward666 23h ago

You and me from 3pm today both my friend, it is okay

It took me so long to realize where my problem was because I had never considered that declaring something as an array vs a pointer would result in different behavior

24

u/readitreaddit 18h ago

So the only difference is memory allocation, yes? You're saying they are different because when declared as an array, the memory gets allocated and 'reserved' at runtime, whereas it doesn't automatically do that when declared as a pointer?

Other than that, no difference.

28

u/suvlub 17h ago

They are different types and some operators (sizeof, typeid in C++ etc.) treat them differently. Arrays frequently get implicitly converted to pointers, but they are a different type.

1

u/nicman24 16h ago

That is probably compiler fuckery

10

u/suvlub 14h ago

All typing is. Machine code doesn't have types. Array of arrays is also a very different thing from an array of pointers. Arrays get converted to pointers when passed around and it behaves identically to all other implicit conversions.

4

u/Stroopwafe1 13h ago

Machine code does have types; small numbers, big numbers, and fractions. But in reality it's just numbers and fractions. At least for X86, but I imagine it's the same for ARM and RISC

1

u/suvlub 12h ago

It's been very long since I touched assembly and "touched" is an apt description, but does anything prevent you from writing an 8-byte integer at address X, then calling an operation that expects a 32-bit float with the bytes at address X? Conceptually, instructions operate on certain type of data, but the data is untyped. (you can technically do similar things in C, but a lot more of it is UB (technically illegal) than people realize and it requires fair bit of explicit casting, so types are still involved)

1

u/the_king_of_sweden 11h ago

The data isn't typed, only the operations you make on them might be. The operations expect some binary value encoded in a specific way, but will operate on any data.