On Mon, 9 Nov 2020, 01:21 Hubert Tong via Lib, <lib_at_[hidden]> wrote:

> It appears C++20 subclause 16.4.6.13 [res.on.exception.handling] allows C
> standard library functions that are present in the C++ standard library to
> be declared as being `noexcept(true)`; however, the same cannot be said of
> POSIX or LSB system interfaces.
>

To make sure I understand, you're talking about POSIX functions such as
read(3) which are not in ISO C, right?

Some guidance would be useful.
>


No standard says what it means to include a POSIX header in a C++ program
at all. While it would probably be useful to say that it's unspecified
whether POSIX APIs are noexcept(true) or noexcept(false) when used in C++,
I don't know where that wording could live. Adding it to POSIX would open a
can of worms, because it's not very useful to say that without saying a lot
more. Adding it to the C++ standard seems wrong, because WG21 doesn't own
those APIs.

I assume the same applies to LSB but I'm much less familiar with that
document.

The attempt to specify a C++ binding for POSIX never got anywhere. Maybe we
should consider publishing an informational TR describing what happens in
real work implementations, without trying to standardise anything.