On Sun, 16 Aug 2020 09:21:24 -0400
Ken Brown via Cygwin <cygwin@cygwin.com> wrote:
> On 8/15/2020 11:53 PM, Takashi Yano via Cygwin wrote:
> > On Sat, 15 Aug 2020 20:38:01 -0300
> > David McFarland via Cygwin <cygwin@cygwin.com> wrote:
> >>
> >> I was just debugging a c++ app (b2 build system from boost), and noticed
> >> that it would appear to exit unexpectedly without an error. This turned
> >> out to be when an unhandled C++ exception was thrown.
> >>
> >> On a fresh install of cygwin with gcc-g++, this program will throw an
> >> exception from the std::string constructor:
> >>
> >> c++ -x c++ - <<END
> >> #include <string>
> >> int main() { std::string str(nullptr); return 0; }
> >> END
> >>
> >> When it's executed from the shell it returns zero, but execution stops
> >> at the exception.
> >>
> >> $ ./a; echo $?
> >> 0
> >>
> >> When executed under gdb, the exception is caught, and the process exits
> >> non-zero when continued:
> >>
> >> (gdb) r
> >> Starting program: /home/corngood/a
> >> [New Thread 4300.0x1390]
> >> [New Thread 4300.0x1d24]
> >> [New Thread 4300.0x1d48]
> >> [New Thread 4300.0x80c]
> >> gdb: unknown target exception 0x20474343 at 0x7ff8d2cfa799
> >> Thread 1 "a" received signal ?, Unknown signal.
> >> 0x00007ff8d2cfa799 in RaiseException () from
> >> /cygdrive/c/WINDOWS/System32/KERNELBASE.dll
> >> (gdb) c
> >> Continuing.
> >> [Thread 4300.0x1d24 exited with code 541541187]
> >> [Thread 4300.0x1870 exited with code 541541187]
> >> [Thread 4300.0x1d48 exited with code 541541187]
> >> [Thread 4300.0x1390 exited with code 541541187]
> >> [Inferior 1 (process 4300) exited with code 04021641503]
> >> (gdb)
> >>
> >> When executed under strace, it exits with an error as expected:
> >>
> >> $ strace -o /dev/null a; echo $?
> >> 67
> >>
> >> That's as far as I've investigated so far.
> >
> > Is this the same issue with
> > https://cygwin.com/pipermail/cygwin/2019-October/242795.html ?
> >
> > As far as I tested, this does not occur in 32-bit cygwin.
>
> This doesn't seem to be a new issue. I found the following report from 6
> years
> ago, on Cygwin 1.7.30 with GCC 4.9.0:
>
> https://stackoverflow.com/questions/24402412/program-executed-on-cygwin-does-not-report-a-thrown-exception
Thanks for the information. But I still wonder why 32-bit and 64-bit
cygwin behave differently.
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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