CXX env var missing!

[alirezaafzalaghaei]

As the project mentioned, I defined the environment variable CXX referring to /usr/bin/g++, but the project raises the following runtime error at the installation process:

RuntimeError: CXX env var missing, needs to point to your target C++ compiler

The error is raised both in the pip install pressio4py and GitHub source code building commands.

export CXX=$(which g++) && sudo pip3 install pressio4py
export CXX=$(which g++) && sudo pip3 install ./pressio4py # build from souce

Finally, the problem has been solved by editing setup.py file, adding os.environ['CXX'] = '/usr/bin/g++' at line 110.

OS: Manjaro,
Python: 3.9,
pip: versions 20 and 21.

[fnrizzi]

hi @alirezaafzalaghaei , thanks for opening this.
Glad to read you were able to solve it, if that solution works fine for you, great :)

This is strange, I just tried your exact commands and it works for me. We never had this issue before.
can you please do this:

export CXX=$(which g++)
env
$CXX --version

and post here the result?

[jtencer]

Did you confirm that which g++ returns the correct path? I've seen an issue with that before (unrelated to pressio). If you're using a bash shell, type seems to be more reliable than which.

Edit: It looks like Francesco had the same thought :)

[alirezaafzalaghaei]

@fnrizzi @jtencer
I'm using Z-Shell plus OMZ plugin. I'd tested installing the package in both shells, but the error was the same. I'd printed the os.environ variable at line 110 of setup.py. As far as I can remember the result of this, differs from the python -u -c 'import os; print(os.environ)' command.This may cause the problem... It's worth noting that I had added export CXX='/usr/bin/g++' to the .zshrc but the problem had not solved. I think the setup.py does not see the current shell variables. The last line of the env command contains CXX=/usr/bin/g++ definition, and the result of the $CXX --version command:

$ export CXX=$(which g++)
$ $CXX --version
g++ (GCC) 11.1.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[fnrizzi]

@alirezaafzalaghaei can you please post here what you get from doing:

export CXX=$(which g++)
env

In your message above i don't see the output of env :)

[alirezaafzalaghaei]

$ export CXX=$(which g++)
$ env
BROWSER=/usr/bin/firefox
COLORFGBG=15;0
COLORTERM=truecolor
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
DESKTOP_SESSION=plasma
DISPLAY=:0
EDITOR=/usr/bin/nano
GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/conficker/.gtkrc-2.0:/home/conficker/.config/gtkrc-2.0
GTK3_MODULES=xapp-gtk3-module
GTK_MODULES=canberra-gtk-module
GTK_RC_FILES=/etc/gtk/gtkrc:/home/conficker/.gtkrc:/home/conficker/.config/gtkrc
HOME=/home/conficker
KDE_APPLICATIONS_AS_SCOPE=1
KDE_FULL_SESSION=true
KDE_SESSION_UID=1000
KDE_SESSION_VERSION=5
KONSOLE_DBUS_SERVICE=:1.50
KONSOLE_DBUS_SESSION=/Sessions/1
KONSOLE_DBUS_WINDOW=/Windows/1
KONSOLE_VERSION=210800
LANG=en_US.UTF-8
LANGUAGE=
LC_ADDRESS=en_US.UTF-8
LC_IDENTIFICATION=en_US.UTF-8
LC_MEASUREMENT=en_US.UTF-8
LC_MONETARY=en_US.UTF-8
LC_NAME=en_US.UTF-8
LC_NUMERIC=en_US.UTF-8
LC_PAPER=en_US.UTF-8
LC_TELEPHONE=en_US.UTF-8
LC_TIME=en_US.UTF-8
LOGNAME=conficker
MAIL=/var/spool/mail/conficker
MKLROOT=/opt/intel/mkl
MOTD_SHOWN=pam
OLDPWD=/home/conficker
PAM_KWALLET5_LOGIN=/run/user/1000/kwallet5.socket
PATH=/home/conficker/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/var/lib/snapd/snap/bin:/home/conficker/.fzf/bin
PROFILEHOME=
PWD=/home/conficker
QT_AUTO_SCREEN_SCALE_FACTOR=0
QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1
SESSION_MANAGER=local/conficker-pc:@/tmp/.ICE-unix/919,unix/conficker-pc:/tmp/.ICE-unix/919
SHELL=/usr/bin/zsh
SHELL_SESSION_ID=66ce82dadcbf4acf8d7768c244307c99
SHLVL=1
SYSTEMD_EXEC_PID=829
TERM=xterm-256color
USER=conficker
WINDOWID=67108871
XAUTHORITY=/tmp/xauth-1000-_0
XCURSOR_SIZE=24
XCURSOR_THEME=Sweet-cursors
XDG_CONFIG_DIRS=/home/conficker/.config/kdedefaults:/etc/xdg
XDG_CURRENT_DESKTOP=KDE
XDG_DATA_DIRS=/home/conficker/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share:/var/lib/snapd/desktop
XDG_RUNTIME_DIR=/run/user/1000
XDG_SEAT=seat0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_SESSION_CLASS=user
XDG_SESSION_DESKTOP=KDE
XDG_SESSION_ID=2
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session1
XDG_SESSION_TYPE=x11
XDG_VTNR=1
_=/usr/bin/env
ZSH=/home/conficker/.oh-my-zsh
PAGER=less
LESS=-R
LSCOLORS=Gxfxcxdxbxegedabagacad
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.webp=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
CXX=/usr/bin/g++```

[jtencer]

Looks like it's in the environment, but somehow not getting included in the python environment? You said there was a difference between what you see when you printed os.environ in setup.py and when you ran the below? What happens if you try:

export CXX=$(which g++)
python -c "import os; print(os.environ['CXX']")

and what happens when you print os.environ in setup.py?

Is it possible that you're executing setup.py with a different python installation?

[fnrizzi]

I also wondering if this has something to do with the zshell since that is the only "different" thing here that I can think of

[alirezaafzalaghaei]

@jtencer
os. environ in the setup.py prints some other variables. I have no idea where they are defined :)

$ export CXX=$(which g++)                                                                                    [~][19:49:08][!2031]
$ python -c "import os; print(os.environ['CXX'])"
/usr/bin/g++

@fnrizzi
As I know most of the *nix operating systems have g++ package installed. I think it's better to check whether the '/usr/bin/g++' file exists or not. If not, raise a runtime error for CXX environment variable.

[fnrizzi]

it is not just checking that it exits, also that it supports C++14.
In any case, yes, we add the checking too at some point.
I will try with the zsh too when i have time to see if i can reproduce this. It is really hard to understand what is going since this is so user specific :)

In any case, if you are able to bypass this step and build and run tests, that is great. Am i right? No surprises there?

[alirezaafzalaghaei]

Fortunately, everything else is okay. The tests are running well. Thanks for your great project :)

[fnrizzi]

thanks @alirezaafzalaghaei !
Btw, we are working on improving this a bit, so we should push an updated version sometime in the new few weeks.
We have made quite a bit of changes on the C++ side, and will likely reflect them in the pressio4py.
The API of pressio4py will pretty much not change, but we will expose more functionalities.