Path: csiph.com!eternal-september.org!feeder.eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c++
Subject: Re: standard error messages in a std::string or in a const char *
Date: Thu, 12 Sep 2019 14:41:22 -0700
Organization: None to speak of
Lines: 30
Message-ID: <lnsgp1b3b1.fsf@kst-u.example.com>
References: <ql98g2$8tf$1@dont-email.me> <ql98je$8tf$2@dont-email.me> <slrnqnhc2b.cdo.grahn+nntp@frailea.sa.invalid> <qlacv3$1d1o$1@adenine.netfront.net> <qlb4o0$m6s$1@dont-email.me> <qlb72g$63i$1@dont-email.me> <qlbabt$q2f$1@dont-email.me> <qlbb35$vji$1@dont-email.me> <qld8vl$knc$3@dont-email.me> <b56acdf7-3f0f-4e37-a21e-596209b3bdcd@googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: reader02.eternal-september.org; posting-host="9405e1ef90ab11981d179ec051d04224"; logging-data="6567"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18yeSoAGqfFkW1ii1D6W/uH"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux)
Cancel-Lock: sha1:P0uoZU1X8+b/HpwS6GgCap/CCk4= sha1:RPY6TlrrWsLly7894u4Q1La74SU=
Xref: csiph.com comp.lang.c++:68371

Thiago Adams <thiago.adams@gmail.com> writes:
> On Thursday, September 12, 2019 at 8:08:46 AM UTC-3, Soviet_Mario wrote:
> ...
>> ahhhh ! Got it. Strangely I had included the (useless) 
>> <cerrno> but not completely consciously, and did not include 
>
> C++ standard is creating differences from the same C header. 
>
> For instance:
> C++ <cerrno> defines a lot of POSIX error codes.
> "E2BIG, EACCES, ..., EXDEV"
> https://en.cppreference.com/w/cpp/error/errno_macros
>
> And C defines only EDOM, EILSEQ and ERANGE
> https://en.cppreference.com/w/c/error/errno_macros

The C standard only requires EDOM, EILSEQ, and ERANGE, but C
implementations can, and commonly do, define additional macros.

Both C and POSIX specifically permit additional E* macros to
be defined.  I don't see such a permission in the C++ standard,
though I could be missing it.

(I'm a little surprised C++ mandates the POSIX error codes, given
that C++ can be implemented on non-POSIX systems.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */