Problem with Geoviewer 3.0.7 on Mac OS High Sierra

Dear Flair-Users,

I have installed Flair and Geoviewer according to the procedure mentionned on the FLAIR website from the source code by compiling with gcc9 (MacPorts gcc9 9.2.0_2) and python3. Flair is working fine, however when I use the “geometry” button on the interface, geoviewer is starting quite well and before displaying the last four drawing views, the interface suddenly stops with the following error message:

Assertion failed: (pthreadret == 0), function _xcb_in_wake_up_next_reader, file xcb_in.c, line 926.
~/local/flair/flair_3.0.7/flair: line 15: 91207 Abort trap: 6 CMD @
Any idea ?


Hi Eric,
it seems related to an update in Mac X11 related port.
We’re trying to identify the problem and propose asap a solution.
Cheers luigi

Hi Eric,
the problem is related to the following ports
xorg-libxcb and xorg-xcb-proto.
Downgrading them to the version 1.13 fixes the problem.

Here how to do it:

$> git clone --single-branch
$> cd macports-ports
$> git checkout b0ba9280eab572558a893dd27e17f1ceade9ab38
$> cd x11/xorg-libxcb
$> sudo port install
$> cd ../xorg-xcb-proto
$> sudo port install

After these instructions the version 1.14 of the two packages have been deactivated, while the version 1.13 is active.
Flair should then work.

Let me know if it works for you.
Cheers luigi

Hi @ebaussan, @luillo,

In case the macports installation is not new,
i.e. the users has followed all the required steps before and flair was working,
then for simplicity he could do:

port installed xorg-libxcb xorg-xcb-proto

and select the xorg-libxcb @1.13.1_0+python37 and xorg-xcb-proto @1.13_2+python37 from the appeared list.

Then in order to activate them (and desactivate the newer versions of them):

sudo port activate xorg-xcb-proto @1.13_2+python37 xorg-libxcb @1.13.1_0+python37

On the other hand, in case of a new installtion, the solution of @luillo is the only way to downgrade.


Hi Luigi and Thanos,

thanks for your help, it is working now !