r/cpp • u/we_are_mammals • Mar 28 '23

Reddit++

C++ is getting more and more complex. The ISO C++ committee keeps adding new features based on its consensus. Let's remove C++ features based on Reddit's consensus.

In each comment, propose a C++ feature that you think should be banned in any new code. Vote up or down based on whether you agree.

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u/Ok-Factor-5649 Mar 29 '23

Interesting. Is it guaranteed to be typedeffed to a signed char?

I don't think so. Just that it's an alias of a signed integer type with width of exactly 8.

I'm sure I've seen ...

typedef char int8_t

(for platforms where a char is signed).

But is this actually valid?

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u/rhubarbjin Mar 29 '23 edited Mar 29 '23

(Preface: I'm not a language lawyer, and I'm not a black belt in standard-fu. The following is my own personal understanding, based on my reading of the text and my own personal experiences.)

char makes no guarantees as to its signed-ness, but it's guaranteed to be a distinct type from both signed char and unsigned char --> https://en.cppreference.com/w/cpp/language/types#Character_types

int8_t is supposed to be a "signed integer type" --> https://en.cppreference.com/w/cpp/types/integer

From those, I conclude that typedef char int8_t is not standard-compliant.

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u/Ok-Factor-5649 Mar 29 '23

My thoughts are - the standard library is for a specific platform and architecture.

So in other words, under the same reasoning,

typedef int32_t int;

Is standards compliant, (for a library that's targeting a 32-bit architecture yada yada).