Re: Can extern "C" functions throw exceptions

From	Paavo Helde <myfirstname@osa.pri.ee>
Newsgroups	comp.lang.c++
Subject	Re: Can extern "C" functions throw exceptions
Date	2021-09-13 09:55 +0300
Organization	A noiseless patient Spider
Message-ID	<shmskb$3ir$1@dont-email.me> (permalink)
References	(1 earlier) <shi5g0$9cu$1@dont-email.me> <shiree$hq9$1@dont-email.me> <shkgol$3cc$2@gioia.aioe.org> <20210912144443.a174f80b419b5694959f26d9@cvine--nospam--.freeserve.co.uk> <shmnso$mct$3@gioia.aioe.org>

Show all headers | View raw

13.09.2021 08:34 Juha Nieminen kirjutas:
> Chris Vine <chris@cvine--nospam--.freeserve.co.uk> wrote:
>> gcc allows you to pass a function pointer
>> with C++ language linkage to a C function expecting a C function
>> pointer, but strictly speaking it is undefined behaviour.
> 
> Does that mean that if you are using a C library and you give it a
> function pointer (eg. a callback function), you ought to make that
> function extern "C"?

Strictly speaking, yes, otherwise the calling conventions might be mixed 
up. But meanstream C++ implementations are using the same calling 
conventions for C and C++ code, so they don't mind.

> 
> How about std::qsort()? Does its comparator function pointer need to be
> declared extern "C"? (Or does the standard require std::qsort() to be
> usable with C++ function pointers directly?)

Indeed, the C++ standard requires qsort to accept both C and C++ 
callbacks. This is a copy-paste from N4842:

void qsort(void* base, size_t nmemb, size_t size, c-compare-pred * compar);
void qsort(void* base, size_t nmemb, size_t size, compare-pred * compar);

Thread

Can extern "C" functions throw exceptions Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 12:35 +0200
  Re: Can extern "C" functions throw exceptions Bo Persson <bo@bo-persson.se> - 2021-09-11 13:49 +0200
    Re: Can extern "C" functions throw exceptions "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-11 13:57 +0200
    Re: Can extern "C" functions throw exceptions Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-11 15:19 +0300
    Re: Can extern "C" functions throw exceptions Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 15:32 +0200
    Re: Can extern "C" functions throw exceptions HorseyWorsey@the_stables.com - 2021-09-11 15:54 +0000
  Re: Can extern "C" functions throw exceptions "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-11 13:55 +0200
    Re: Can extern "C" functions throw exceptions Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 15:34 +0200
      Re: Can extern "C" functions throw exceptions Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-11 15:58 +0200
      Re: Can extern "C" functions throw exceptions "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-09-11 17:00 +0200
        Re: Can extern "C" functions throw exceptions "daniel...@gmail.com" <danielaparker@gmail.com> - 2021-10-06 13:36 -0700
          Re: Can extern "C" functions throw exceptions Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-06 20:42 +0000
            Re: Can extern "C" functions throw exceptions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-06 16:12 -0700
              Re: Can extern "C" functions throw exceptions Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-06 23:22 +0000
                Re: Can extern "C" functions throw exceptions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-06 17:03 -0700
    Re: Can extern "C" functions throw exceptions HorseyWorsey@the_stables.com - 2021-09-11 15:56 +0000
    Re: Can extern "C" functions throw exceptions David Brown <david.brown@hesbynett.no> - 2021-09-11 20:10 +0200
      Re: Can extern "C" functions throw exceptions Juha Nieminen <nospam@thanks.invalid> - 2021-09-12 09:20 +0000
        Re: Can extern "C" functions throw exceptions Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-12 12:34 +0300
        Re: Can extern "C" functions throw exceptions David Brown <david.brown@hesbynett.no> - 2021-09-12 12:24 +0200
          Re: Can extern "C" functions throw exceptions Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-12 12:29 +0200
        Re: Can extern "C" functions throw exceptions Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-09-12 14:44 +0100
          Re: Can extern "C" functions throw exceptions James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-12 23:13 -0400
            Re: Can extern "C" functions throw exceptions David Brown <david.brown@hesbynett.no> - 2021-09-13 09:30 +0200
            Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-06 13:12 -0700
              Re: Can extern "C" functions throw exceptions "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-10-07 07:09 -0700
                Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-14 15:21 -0800
                Re: Can extern "C" functions throw exceptions Richard Damon <Richard@Damon-Family.org> - 2021-12-14 21:17 -0500
                Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-16 04:21 -0800
                Re: Can extern "C" functions throw exceptions "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-12-14 19:06 -0800
                Re: Can extern "C" functions throw exceptions Ian Collins <ian-news@hotmail.com> - 2021-12-16 13:14 +1300
                Re: Can extern "C" functions throw exceptions "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-15 18:05 -0800
                Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-16 04:37 -0800
                Re: Can extern "C" functions throw exceptions Ian Collins <ian-news@hotmail.com> - 2021-12-17 09:39 +1300
                Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-16 19:24 -0800
                Re: Can extern "C" functions throw exceptions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-16 04:29 -0800
          Re: Can extern "C" functions throw exceptions Juha Nieminen <nospam@thanks.invalid> - 2021-09-13 05:34 +0000
            Re: Can extern "C" functions throw exceptions Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-13 09:55 +0300
  Re: Can extern "C" functions throw exceptions Paavo Helde <myfirstname@osa.pri.ee> - 2021-09-11 15:12 +0300
  Re: Can extern "C" functions throw exceptions red floyd <no.spam.here@its.invalid> - 2021-09-13 13:21 -0700

csiph-web