Re: So You Think You Can Const?

On 01/09/25 12:12 AM, Julio Di Egidio wrote:

I do not understand that: `free` is changing the pointed data, so how can `const void *` even be "correct"?

`free` is destroying the pointed data.
Every object in C object model has to be created (when its lifetime begins) and has to be eventually destroyed (when its lifetime ends). This applies to all objects, including `const` ones (!). Lifetime of a `const` objects also ends eventually, which means that `const` object has to be destroyable. No way around it.
So, destruction is not really a "modifying" operation. Destruction of an object is a special case, it's a meta-operaton, which needs special treatment. We have to be able to destroy `const` objects as well, regardless of how they were created/allocated. And in C destruction of dynamically created objects is essentially embodied in `free`. So, `free` is a meta-operation, which has to be able to destroy `const` objects.
This, for example, is mirrored in C++ as well, where `delete` is immediately applicable to pointers to `const` objects. No reason to make `free` behave differently in C.
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Best regards,
Andrey