> Just use POSIX exit(3)!
I did switch my code: #ifdef __CYGWIN__ exit(x); #else ExitProcess(x); #endif . I think the problem is actually in how "Cygwin bash" aka Cygwin, computes the exit code in exec/spawn/system. I.e. it recognizes it is running a Cygwin exe or a native exe and does things differently. I admit I didn't read or debug much. In one run I was debugging I did seem to see a crash in some DllMain(process detach), without symbols, and then I seemed to see ExitProcess(1 or 2) become ExitProcess(0xXX00) and then I started wondering if Cygwin somewhere is only taking the lower 8 bits, since I know that is a thing in some code. But I didn't dig into this further before trying the simple case, which I don't think crashes and really does NtTerminateProcess(1). - Jay ________________________________ From: Brian Inglis <brian.ing...@systematicsw.ab.ca> Sent: Thursday, January 13, 2022 5:19 PM To: cygwin@cygwin.com <cygwin@cygwin.com> Cc: Jay K <jayk...@hotmail.com> Subject: Re: ExitProcess does not work in Cygwin? On 2022-01-13 10:07, Kaz Kylheku (Cygwin) wrote: > On 2022-01-13 05:40, Eliot Moss wrote: >> On 1/13/2022 1:39 AM, Jay K wrote: >>> ExitProcess does not work in Cygwin? Just use POSIX exit(3)! >> ExitProcess does not appear to be a POSIX function. > > This is a real issue worth looking into. Though ExitProcess isn't a POSIX > function, Cygwin can capture the termination status of non-Cygwin programs. > > The concept of termination status cannot be entirely walled off in a > private Cygwin garden; it belongs to the underlying platform. > > In Cygwin, I can do this: > > C:\Cygwin\cygwin64\home\kaz>exit 1 > 1:BLACKBOX:~$ > 1:BLACKBOX:~$ echo $? > 1 > 0:BLACKBOX:~$ cmd > Microsoft Windows [Version 10.0.19042.1052] > (c) Microsoft Corporation. All rights reserved. > > C:\Cygwin\cygwin64\home\kaz>exit 0 > 0:BLACKBOX:~$ > > The number in my Bash prompt is the last exit code. As you can see, > the non-Cygwin CMD.EXE program produces a termination code which > is recognized in the Cygwin world. > > Most likely it does that via ExitProcess. > > It is odd if calling ExitProcess in a Cygwin process causes > a Cygwin parent not to similarly process the status, as seems > to be shown by Jay's test cases. > > Cygwin supports non-POSIX programming; you can write GUI applications > using Win32 calls for instance. > > (Now I agree that for exiting your process, even if it's a GUI > application using numerous win32 calls, you should probably do it the > Cygwin way, and use exit, or return from main. But still ...) Cygwin installs at-exit handlers and it is likely that when these have finished, they return a Cygwin exit status if passed by the POSIX function, perhaps unless some error has occurred during at-exit handling. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.] -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
