Re: [asio-users] Can't catch Boost.Asio exceptions inside coroutines

[Sergey S. <rk...@rk...>]

Solved this with #define BOOST_ASIO_DISABLE_THREADS

I've compiled gdb for Windows and started the test program with it. On
Windows there were 3 threads and on Linux only 1 so I tried to
recompile Boost with threadapi=pthread (just in case there's an issue
with threading) but in the end it didn't compile libboost_thread*.a
and I gave up. After a while I realized that the exception could be
thrown in one thread and caught (unsuccessfully) in the main thread or
some other so I googled for how to disable ASIO threads and that
really helped.

MXE uses threadapi=win32 and threading=multi, probably switching the
latter to single and recompiling boost would help as well but it seems
not to be an easy task with MXE. As I found out there's little to no
info about that threading option (found only this answer:
http://stackoverflow.com/questions/20859761/what-exactly-does-threading-multi-do-when-compiling-boost
and it doesn't mention any issues with exceptions) so I don't know if
it breaks something else if I change it and what exactly changes in
multithreaded boost. For instance, how to deal with exceptions in my
case. Maybe that's a flaw in ASIO itself but I'd refrain from drawing
any conclusions.

Honestly, I don't like it when an abstraction leaks this badly and
instead of added "behind the scenes" efficiency I have to deal with
uncaught exceptions that are clearly have to be caught in this
simplest piece of code.

2016-10-27 9:01 GMT+03:00 Sergey Shpikin <rk...@rk...>:
> Good to know that at least one configuration is working, thank you for
> testing! That MinGW build is for Windows, unfortunately, and I'd like
> to compile on Linux for Windows.
>
> 2016-10-27 8:40 GMT+03:00 niXman <i.n...@au...>:
>> Sergey Shpikin 2016-10-26 18:48:
>>> I have this little example of Boost.Asio code:
>>> http://codepad.org/tuQedXI7 It works as expected on Linux producing
>>> 1
>>> 2
>>> Caught Host not found (authoritative)
>>>
>>> but on Windows it crashes with:
>>> 1
>>> 2
>>> terminate called after throwing an instance of
>>> 'boost::system::system_error'
>>> what():  Unknown error
>>>
>>> Tested on Windows Server 2008, Windows 7 and Wine, everything is the
>>> same. I'm compiling on Linux for Windows with MXE ( http://mxe.cc/ )
>>> on GCC 4.9.4, Boost version is 1.60.0. I'm really stuck at this point
>>> as nothing in Google looks a valid solution for the case and I already
>>> have a working application on Linux but it crashes on any network
>>> error on Windows.
>>>
>>> On Windows coroutines prevent any exceptions from being caught when
>>> the program is compiled with -O1/2/3 but they're caught with -O0 or
>>> -Os (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54267 — this is
>>> about GCC on FreeBSD but the same seemingly applies to MinGW).
>>> However, boost's own exceptions, like the aforementioned
>>> boost::system::system_error, still can't be caught.
>>
>> Works as expected for me using i686-6.2.0-release-posix-dwarf-rev1[1] &
>> boost-1.62.
>>
>>
>>
>> [1]
>> https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/6.2.0/threads-posix/dwarf/i686-6.2.0-release-posix-dwarf-rt_v5-rev1.7z
>>
>> --
>> Regards, niXman
>> ___________________________________________________
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>> http://sourceforge.net/projects/mingw-w64/
>>
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