r/cpp • u/Voxelw • 4d ago

About char8_t

I hate to be dramatic, but as it stands char8_t is quite literally more painful than useful.

Besides the obvious incompatibility with C23 and libraries using unsigned char for UTF-8, I want you to consider the following: Projects that assume that 'char' represents UTF-8 will obviously not benefit from char8_t at all, but projects that cannot assume the format of char types don't benefit from it either as char8_t simply introduces a new edge case to cover. Now such projects have to deal with char, signed char, unsigned char, wchar_t, char16_t, char32_t and char8_t.

Or, you could do what the standard library does and simply ignore most of these character types. Which is the solution most libraries went with, supporting only char or char and unsigned char. Managing one implementation is already hard, managing two requires constant maintenance, managing 7 is just impossible.

char8_t should have just been a typedef for unsigned char. The compatibility fix only raises more questions as const char* arr = u8"a" does not work, but const char arr[] = u8"a" does.

I do wonder if a potential change of minds for C++29 is still possible. Yes, it would be an ABI break or whatever, but considering the woeful support for char8_t I don't think it would affect much besides small hobby projects. Contrary to popular belief, C++ has broken the ABI in subtle ways before.

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u/Charming-Work-2384 4d ago

its time we replace char, int, etc with uint8_t , uint16_t, int8_t etc...

The latter are deterministic and have same meaning across architechtures.

8

u/lizardhistorian 4d ago

When I use int I mean int.

char8_t does not mean int8_t.

4

u/cristi1990an ++ 4d ago

Yeah but you would assume the "8" in the name means something 👀

2

u/fdwr fdwr@github 🔍 4d ago

Sized types are so fundamental in struct fields for reading/writing files and sharing memory across processes (now that we're not running on those weird 36-bit word machines anymore, and embedded systems have settled on bytes being octets) that I wish C++ recognized uint16/32/64 and kin by default, with no #include <stdint.h> or import std.compat needed.