Recompilation problems opencv (python3-cv2 --> python3.8)

Brian Inglis
Fri Jan 15 17:14:57 GMT 2021

On 2021-01-15 01:13, wilhelm-eger--- via Cygwin wrote:
> Gesendet: Donnerstag, 14. Januar 2021 um 23:52 Uhr
>> Please try by downloading the complete Cygwin source package, and try a vanilla
>> rebuild first with zero changes, then change only the .cygport VERSION= to the
>> latest, rebuild, and fix any problems with that as you go.
> I have done the following
> mkdir opencv
> cd opencv
> git clone .
> cygport opencv.cygport fetch
> cygport opencv.cygport all
> Same error.
> Is there any other location where I could get the opencv source package from?

Check your email host location:

$ geoiplookup
GeoIP Country Edition: DE, Germany
GeoIP City Edition, Rev 1: DE, 01, Baden-Wurttemberg, Karlsruhe, 76137, 
49.001900, 8.428700, 0, 0
GeoIP ASNum Edition: AS8560 1&1 Internet SE

Check Cygwin German mirror locations for one nearby:

$ sed '/^\s\+[^;]\+;\([^;]\+\);Europe;Germany$/!d;s!!\1!' /etc/setup/setup.rc | 
sort -u | xargs -l1 geoiplookup
$ geoiplookup
GeoIP Country Edition: DE, Germany
GeoIP City Edition, Rev 1: DE, 01, Baden-Wurttemberg, Stuttgart, 70173, 
48.766701, 9.183300, 0, 0
GeoIP ASNum Edition: AS553 Universitaet Stuttgart

in same Land, lat/long diff about .25/.75, and about 61km great circle distance.

Find mirror URLs:

$ fgrep /etc/setup/setup.rc;;Europe;Germany;;Europe;Germany;;Europe;Germany

Find source package:

$ grep -m1 '^source:\s.*opencv' ~/mirror/x86_64/setup.ini
source: x86_64/release/opencv/opencv-3.4.1-2-src.tar.xz 138322784 

Download source package:

$ curl -OJRSs
$ wget -N -nv

$ tar -xf opencv-3.4.1-2-src.tar.xz

Also package *patches* visible from:

but patches directly downloadbale from:

[thanks to Achim for pointers]



and you can pick later branches or tags for patches for later versions as you 
need from these repos: cygport can use URLs or local file names in 
PATCH_URI="..." and the string content may be a separate line per patch, usually 
with a leading tab.

> Btw. there is no need to change to another Version, I just want to have cv2
> also in python3.8 working. From what I have experienced with this package I
> assume that this would also not compile with python3.6 atm. Seems to be a
> cmake or gcc error to me.
First check your current packages, toolchains, and libraries against a known 
good working set of vanilla sources at an earlier version that should have no 
issues, then work your way up to newer versions adding difficulties! ;^>

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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