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docs: Clarify exactly how C is bad at passing arrays to functions #63

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Jul 7, 2024
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docs: Clarify exactly how C is bad at passing arrays to functions #63

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7 changes: 4 additions & 3 deletions docs/src/kdl-script/types/arrays.md
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Expand Up @@ -4,16 +4,17 @@ KDLScript array types like `[u32; 4]` have the layout/repr you would expect from

But there's a problem with passing them by-value: C is supremely fucking weird about passing arrays by value if they're not wrapped in a struct.

This is actually sugar for pass-by-reference (and largely decays into `u32*`):
This is actually sugar for pass-by-reference (and largely decays into `uint32_t*`):

```C
void blah(u32[4] array);
void blah(uint32_t array[4]);
```

And this doesn't even compile:

```C
u32[4] blah();
uint32_t[4] blah(); // invalid syntax
uint32_t blah()[4]; // valid syntax, but still disallowed
```

To avoid trying to squish weird square pegs in round holes, passing an array by-value like this in KDLScript should indeed mean passing it by-value! C/C++ backends should *simply refuse to lower such a KDLScript program and produce an error*. Rust backends are free to lower it in the obvious way. If you want to test the C way, use this:
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