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by ryukoposting 979 days ago
It's not entirely true that "const" is "just a comment," depending on the use case. In machines with super-limited RAM you can use const on globals to tell the compiler "put this in .rodata"

In other words, "const" (in a global context) can tell the compiler "you don't have to copy this to RAM, just read it directly from non-volatile storage." Obviously, that would be undesirable on a desktop computer, but if you're dealing with a wee little microcontroller, it's very helpful.
2 comments
nathanrf 979 days ago
`const`-as-comment is specifically limited to pointers and references - `const` on objects definitely does change semantics (it is always UB to attempt to modify a `const` object).

Another good example is string literals (except when initializing a non-const `char[]` variable), which are often allocated in read-only data in the same way, since they are const objects too.

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Kranar 979 days ago
The comment specifically referred to references and pointers whereas your example does not.
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