Re: Exception handling
Re: Exception handling
- Subject: Re: Exception handling
- From: Alastair Houghton <email@hidden>
- Date: Sat, 16 Jun 2018 15:25:15 +0100
On 15 Jun 2018, at 19:30, Jens Alfke <email@hidden> wrote:
>
>> On Jun 14, 2018, at 5:58 PM, Quincey Morris
>> <email@hidden> wrote:
>>
>> as someone already mentioned, NSExceptions can’t successfully cross
>> dylib/framework boundaries.
>
> They can, actually; there is no problem with this at the ABI/runtime level.
>
> I think what you mean is that most libraries/frameworks don't make guarantees
> about properly handling exceptions thrown into them, i.e. from a call into
> external code. Some C++ libraries do guarantee this (especially libc++), and
> even without guarantees a typical C++ lib using RAII will be relatively safe,
> but Objective-C code usually isn't written to be exception-safe, and C code
> of course can't be.
Quite, though in principle there’s no reason C code couldn’t be exception safe,
it’s just that there’s no language support for it (except on Windows where
there are extensions to support SEH), so the C code would have to know about
the relevant runtime data structures and associated behaviour. In practice,
it’s very unlikely you’d ever find exception-safe C code, except in a language
runtime or - rarely - on Windows when it’s been written to use SEH.
Kind regards,
Alastair.
--
http://alastairs-place.net
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