Re: Errors compiling Libobjc2

[David Chisnall]

> On 2 Jul 2019, at 23:23, Riccardo Mottola <address@hidden> wrote:
> 
> Hi,
> 
> On 2019-06-21 16:13:58 +0000 David Chisnall <address@hidden> wrote:
> 
>> On 21/06/2019 16:08, Riccardo Mottola wrote:
>>> ld: error: undefined symbol: _Unwind_Resume
>> It looks as if your toolchain doesn't automatically link anything that 
>> provides the exception ABI.  On most *NIX systems this comes from something 
>> called libgcc_s.so (which, on FreeBSD, is actually LLVM's compiler-rt - on 
>> some platforms it's installed as such).  What happens when you compile a C 
>> program that uses -fexceptions and __attribute__((cleanup)) on OpenBSD?  
>> Does it link something that provides these symbols?
> 
> I did some research and found that Unwind_Resume is in libc++, however to get 
> all Unwind symbols, libc++abi is needed.

_Unwind_Resume should not be in libc++, it’s from the unwind library, which is 
two layers down.

Note that if you’re on a platform that uses libc++abi, then C++ / Objective-C 
exception interop won’t work.  Please encourage OpenBSD to use libcxxrt or 
libsupc++ instead.  libc++abi is not a drop-in replacement for libsupc++.

David