Implicitly converting to underlying type

Asked Oct 15 '20 at 15:27

Active Oct 15 '20 at 18:42

Viewed 28 times

I have some driver code which looks like this:

static const uint8_t PREAMBLE = 0xA0;

enum class Channel: const uint8_t {
    0 = 0x0,
    1 = 0x8
};

void foo(Channel chan) {
    bar(PREAMBLE | channel);
}

Where the intention is for users to be able to pass in a channel by an ID to foo rather than the particular mask and then my code handles forming the correct address. The problem is the compiler complains that he does not know how to XOR Channel and const uint8_t, even though the underlying types are the same. Is there some extra hint (without explicit casting) I can provide to make this work?

edited Oct 15 '20 at 18:42

Pete Becker

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asked Oct 15 '20 at 15:27

Madden

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Your example can't compile. Please post code which is valid. – Tanveer Badar Oct 15 '20 at 15:29
this would be one option: https://godbolt.org/z/4sMqna – Alan Birtles Oct 15 '20 at 15:32
I've never seen `enum class` used with a `const` backing type. What are the implications of that? – François Andrieux Oct 15 '20 at 15:33
1

@FrançoisAndrieux - Obfuscation. For the compiler, however, it means something to ignore https://timsong-cpp.github.io/cppwp/n4861/enum#dcl.enum-2.sentence-4 – StoryTeller - Unslander Monica Oct 15 '20 at 15:35
@FrançoisAndrieux Actually that was a holdover from just making sure the `const`ness of `PREAMBLE` wasn't interfering. I haven't though of what this would actually mean but not much I would guess – Madden Oct 15 '20 at 15:35

Implicitly converting to underlying type

0 Answers0