Re: scons v4.3.0-1 outputs nothing on cygwin v2. 3.1

[Doug Henderson <djndnbvg@gmail.com>]

Please show us the results of the following two commands:

$ which -a alternatives

$ ls -glo $( which -a alternatives )

Please note that /usr/sbin/alternatives must be executed in an
elevated shell. The folder containing it is not normally included in
the path for a non-elevated shell. It is considered to be a command
used by the administrator rather than the user.

The easiest way to do this is to right click on the "Cygwin Terminal"
icon on the desktop or a shortcut to it in the start menu and click on
Run as administrator.

Then execute

$ /usr/sbin/alternatives --verbose --auto python

If you see this message "failed to replace
/var/lib/alternatives/python with /var/lib/alternatives/python.new:
Permission denied", you are not running in an elevated shell.

If you see this message "link points to no alternative -- setting mode
to manual", please run this command

$ /usr/sbin/alternatives --test --auto python

which will show which link is missing, as there will be a blank line
after the link name instead of a priority. This may not be a serious
problem, but I am investigating why it occurs.

BTW, this is the output on my system:
$ /usr/sbin/alternatives --display python
python - status is manual.
 link currently points to /usr/bin/python3.9.exe
/usr/bin/python2.7 - priority 27
/usr/bin/python3.8 - priority 38
/usr/bin/python3.6 - priority 36
/usr/bin/python3.7 - priority 37
/usr/bin/python3.9 - priority 39
Current `best' version is /usr/bin/python3.9.

With this setup, using "python" runs "version 3.9", "python2" runs
"version 2.7", "python3.x" runs the corresponding "version 3.x".
"python3" gives "-bash: python3: command not found".


HTH
Doug (alternatives maintainer)


On Sun, May 15, 2022 at 2:44 PM Brian Inglis
<Brian.Inglis@systematicsw.ab.ca> wrote:
>
> On 2022-05-15 11:10, Martin Ortuno wrote:
> > Here the information you requested:
> > $ ls -glo /usr/bin/python
> > lrwxrwxrwx 1 13 Jun  3  2015 /usr/bin/python -> python2.7.exe


> > $ alternatives --display python
> > python - status is auto.
> > link currently points to /usr/bin/python3.9
> > /usr/bin/python3.9 - priority 39
> > Current `best' version is /usr/bin/python3.9.

This is the expected display when you have only python3.9 installed. - Doug

>
> That makes no sense, your system is messed up:
>
> "link currently points to /usr/bin/python3.9"
>
> implies "/usr/bin/python -> python3.9"
>
> but you have "/usr/bin/python -> python2.7.exe"!
>
> To try to fix that, please try running:
>
>         $ alternatives --verbose --auto python
>
> and please report the output and where the links now go.
>
>
> > El vie., 13 de mayo de 2022 5:47 p. m., Brian Inglis <
> > Brian.Inglis@systematicsw.ab.ca> escribió:
> >
> >> On 2022-05-13 16:16, Martin Ortuno wrote:
> >>> El vie., 13 de mayo de 2022 5:12 p. m., William Deegan escribió:
> >>>> On Fri, May 13, 2022 at 1:41 PM Martin Ortuno wrote:
> >>>>> El vie., 13 de mayo de 2022 3:30 p. m., Martin Ortuno escribió:
> >>>>>> El vie., 13 de mayo de 2022 11:51 a. m., William Deegan escribió:
> >>   >>>>> On Fri, May 13, 2022 at 8:46 AM Martin Ortuno wrote:>>>>>> On one
> >> project we are using cygwin v2.3.1 for 32 bits as a
> >>   >>>>>> building environment... We are integrating a library that
> >>   >>>>>> is built scons, I tried to run scons v4.3.0-1 but when I
> >>   >>>>>> prompt scons on the command line.
> >>   >>>>>> Scons -v outputs nothing...
> >>   >>>>>> I would appreciate your support in this matters...
> >>
> >>>>>>> Are you sure you're running scons from cygwin?
> >>>>>>> Which version of python do you have installed?
> >>
> >>>>>> On the cygwin envuronment i have both python 2.7.10 and python 3.4.3,
> >>>>>> the one which is by default is python 2...
> >>>>>> Pretty sure that's the reason why is not working, i think we need
> >> python
> >>>>>> 3.9 for scons...
> >>>>>> The problem now is that i cannot install successfully python 3.9. I
> >>>>>> tried with the setup-x86, just updating python3... However after that
> >>>>>> python3 stops working...
> >>>>>> I'd appreciate any advice or support...
> >>
> >>>>> Actually i tried to open python3.9 from windows directly  and then the
> >>>>> application crashes saying:
> >>>>> "The procedure entry point __locale_ctype_ptr could not be located in
> >> the
> >>>>> dynamic link library
> >>>>> C:\Path\toCygwin\bin\libpython3.9.dll"
> >>
> >>>> vi `which scons`
> >>>> and see which python it's trying to use.
> >>>> (from within your cygwin shell)
> >>>> Very surprised you get no output.
> >>
> >>   > I am prompting which scons:
> >>   > Output:
> >>   > /bin/scons/
> >>
> >> That output makes no sense!
> >> Please paste actual commands and outputs from terminal.
> >>
> >> Might be more useful running:
> >>
> >>          $ ls -glo /usr/bin/python
> >>          lrwxrwxrwx 1 24 Feb 17  2021 /usr/bin/python ->
> >> /etc/alternatives/python
> >>          $ alternatives --display python
> >>          python - status is auto.
> >>           link currently points to /usr/bin/python3.9
> >>          /usr/bin/python2.7 - priority 27
> >>          /usr/bin/python3.8 - priority 38
> >>          /usr/bin/python3.7 - priority 37
> >>          /usr/bin/python3.6 - priority 36
> >>          /usr/bin/python3.9 - priority 39
> >>          Current `best' version is /usr/bin/python3.9.
> >>          $ cygcheck -c scons
> >>          Cygwin Package Information
> >>          Package              Version        Status
> >>          scons                ...            OK
> >>          $ head -n1 /usr/bin/scons
> >>          #!/usr/bin/python...
>
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-- 
Doug Henderson, Calgary, Alberta, Canada - from gmail.com