On 8/15/20 11:38 PM, David McFarland via Cygwin 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.Can you try if different (older) GCC versions exhibit the same problem? You'll need to recompile your example with said version as well.
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