Failed assertion dialog box

[William M. (Mike) Miller]

On Sat, Nov 14, 2020 at 10:26 AM Lemures Lemniscati via Cygwin <
cygwin@cygwin.com> wrote:

> On Sat, 14 Nov 2020 09:12:11 -0500, William M. (Mike) Miller
> > On Sat, Nov 14, 2020 at 12:39 AM Lemures Lemniscati via Cygwin <
> > cygwin@cygwin.com> wrote:
> >
> > > On Sat, 14 Nov 2020 04:37:43 +0000, André Bleau via Cygwin
> > > >
> > > > On Fri, Nov 13, 2020 at 10:45 PM Duncan Roe
> > > > wrote:
> > > >
> > > > > Hi William,
> > > > >
> > > > > On Fri, Nov 13, 2020 at 12:27:57PM -0500, cygwin wrote:
> > > > > > I've run into a problem running a collection of tests under
> Cygwin
> > > and I
> > > > > > wonder if anyone can suggest a way around it.
> > > > > >
> > > > > > The problem occurs when a program being run fails a C/C++ runtime
> > > > > > assertion. Ordinarily, this just writes an error message on
> stderr
> > > and
> > > > > > aborts. Under Cygwin, however, if both stdin and stderr are
> > > redirected to
> > > > > > files, the program instead pops up a dialog box that must be
> > > > > interactively
> > > > > > dismissed before the failed program will exit - holding up all
> the
> > > tests
> > > > > > that follow it.
> > > > > >
> > > > > > Specifically, if I have the following as assert.cpp:
> > > > > >
> > > > > >     #include <assert.h>
> > > > > >     int main() {
> > > > > >       assert(false);
> > > > > >     }
> > > > > >
> > > > > > and say
> > > > > >
> > > > > >     gcc assert.cpp
> > > > > >     ./a.exe < /dev/null > output 2>&1
> > > > > >
> > > > > > I get an error dialog box saying
> > > > > >
> > > > > >     Failed assertion
> > > > > >         false
> > > > > >     at line 3 of file assert.cpp
> > > > > >     in function int main()
> > > > > >
> > > > > > If I omit either the stdin or the stderr redirection, the program
> > > behaves
> > > > > > as desired with no dialog box.
> > > > > >
> > > > > > Is there an environment setting or compiler command-line option
> I can
> > > > > give
> > > > > > to suppress the dialog box and always just write a message to
> stderr
> > > and
> > > > > > abort? Thanks for any insights.
> > > > >
> > > > > Your example WFFM, (Cygwin64, gcc 10.2.0, everything else also up
> to
> > > date).
> > > > >
> > > > > Do you still see this behaviour if you run the installer?
> > > > >
> > > >
> > > > Thanks for your reply; unfortunately, yes, it does. I had refreshed
> > > > the installation fairly recently, and running the installer only
> updated
> > > a
> > > > few things, not cygwin.dll and not gcc; my installation is the same
> as
> > > > yours. I've tried it with three different shells (tcsh, bash, mksh)
> and
> > > > with both gcc and clang, and all have the same behavior.
> (Interestingly,
> > > if
> > > > I compile the example with MSVC and run it in a Cygwin shell, it does
> > > _not_
> > > > pop up an error dialog box, so presumably it's in the Cygwin runtime,
> > > > specifically the definition of __assert_func.)
> > > >
> > > > I see the same behavior as William:
> > > >
> > > > ./a.exe < /dev/null > output.txt 2>&1
> > > > pops a message box.
> > > >
> > > > gcc (GCC) 10.2.0
> > > > CYGWIN_NT-10.0 XXX 3.1.7(0.340/5/3) 2020-08-22 17:48 x86_64 Cygwin
> > > > mintty 3.4.1 (x86_64-pc-cygwin)
> > > >
> > > > - André Bleau
> > >
> > > It works fine for me.
> > > Can you check 'gcc -M assert.cpp' ?
> > > My result is:
> > >
> > > $ gcc -M assert.cpp
> > > assert.o: assert.cpp /usr/include/assert.h /usr/include/_ansi.h \
> > >  /usr/include/newlib.h /usr/include/_newlib_version.h \
> > >  /usr/include/sys/config.h /usr/include/machine/ieeefp.h \
> > >  /usr/include/sys/features.h /usr/include/cygwin/config.h
> > >
> >
> > Mine is identical. (Same for "uname -a" output, which André posted
> above.)
> >
> > The fact that you and André don't get a dialog box gives me hope that
> > there's something in the environment or installation that controls that
> > behavior. (Just to make certain, "works find for me" means that you ran
> the
> > executable, redirecting both stdin and stderror, and did not get an error
> > popup, right?)
>
> Sorry, I tested on a very old machine (CYGWIN_NT-6.1),
> on which no error popup occurred.
>
> But on Windows 10 (CYGWIN_NT-10.0), it does not work on Windows 10,
> and brings an error popup.
>

Ah, that makes sense; I was previously doing this testing on an older
machine (now defunct, so I can't check versions) and didn't have this
issue. Thanks for the update.

-- 
William M. (Mike) Miller | Edison Design Group
william.m.miller@gmail.com