bug#49524: closed (28.0.50; make-serial-process is not portable)

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Your message dated Tue, 13 Jul 2021 09:11:12 -0400
with message-id <25a83b24-fa7a-f0f7-a105-2596e48ca9a7@cornell.edu>
and subject line Re: bug#49524: 28.0.50; make-serial-process is not portable
has caused the debbugs.gnu.org bug report #49524,
regarding 28.0.50; make-serial-process is not portable
to be marked as done.

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49524: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=49524
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> --- Begin Message ---
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> Subject: 
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> 28.0.50; make-serial-process is not portable
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> Date: 
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> Sun, 11 Jul 2021 11:24:58 -0400
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> User-agent: 
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> Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0
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> Fmake_serial_process calls Fserial_process_configure, which calls 
> serial_configure, which calls cfsetspeed with the speed argument equal to the 
> numerical baud rate (e.g., 9600).  But the documentation of cfsetspeed says that 
> the speed argument must be one of the Bnnn constants defined in termios.h (e.g., 
> B9600).  See, for example,
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>   https://man7.org/linux/man-pages/man3/termios.3.html
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> This incorrect call of cfsetspeed happens to succeed on GNU/Linux because 
> glibc's cfsetspeed allows the argument to be the numerical baud rate, which it 
> converts to the appropriate Bnnn constant.  But I don't think emacs should be 
> relying on this undocumented behavior.  In particular, this doesn't work on 
> Cygwin.  And it wouldn't even work on GNU/Linux if emacs used the cfsetspeed 
> replacement defined in sysdep.c instead of glibc's cfsetspeed.
>
> I think the way to fix this is to imitate the glibc code that converts the baud 
> rate to a Bnnn constant, but maybe someone has a better idea.
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> By the way, I came across this issue while investigating the failure of 
> process-tests/fd-setsize-no-crash/make-serial-process on Cygwin.
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> --- Begin Message ---
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> Subject: 
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> Re: bug#49524: 28.0.50; make-serial-process is not portable
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> Date: 
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> Tue, 13 Jul 2021 09:11:12 -0400
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> User-agent: 
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> Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0
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> On 7/13/2021 7:19 AM, Eli Zaretskii wrote:
> > > From: Ken Brown <kbrown@cornell.edu>
> > > Cc: 49524@debbugs.gnu.org
> > > Date: Mon, 12 Jul 2021 17:35:40 -0400
> > >
> > > So I should probably remove the reference to non-glibc platforms in my commit
> > > message.
> >
> > Yes, something to the effect of compliance with advertised APIs would
> > probably be better.
>
> Done.  Closing.
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> --- End Message ---