Getting value of environment variable

[voidtrance]

I've done some searching on this but I can find a definitive answer and/or example.

How can I get the value of an environment variable inside a meson.build file. I want perform some custom actions based on an environment variable.

[dcbaker]

Please don't. Meson isn't designed to be configured based on environment variables, but on command line (or machine file) specified options, or based on information about the build/host/target machines.

[voidtrance]

I didn't realize there was an environment variable set for python "editable installs"?

As a matter of curiosity, what's special about those anyway, that you can't just do what most builds do and point your IDE to the primary compile_commands.json created in the build directory?

The directory where the file is created is not static. It's based on the CPython version being used. So, it could change over the life of the project. Also, I use emacs and configuring it to auto-find the directory with the file looks like a pain. To me, it just seems simpler to add a custom rule to copy the file to the top directory.

To make matters worse (for me), I am using a mounted filesystem that does not support symlinks, so I can't just create a symlink to the file and forget about it.

[eli-schwartz]

The directory where the file is created is not static. It's based on the CPython version being used. So, it could change over the life of the project. Also, I use emacs and configuring it to auto-find the directory with the file looks like a pain. To me, it just seems simpler to add a custom rule to copy the file to the top directory.

The file is always created at the top of the builddir -- it has no relation to cpython versions.

The builddir may be created in arbitrary locations though -- from recollection, meson-python will create a random one using the tempfile module, which again has nothing to do with cpython version. But it has an option to pass in a builddir name that you would rather use, so you can make this be a stable location.

[voidtrance]

The directory where the file is created is not static. It's based on the CPython version being used. So, it could change over the life of the project. Also, I use emacs and configuring it to auto-find the directory with the file looks like a pain. To me, it just seems simpler to add a custom rule to copy the file to the top directory.

The file is always created at the top of the builddir -- it has no relation to cpython versions.

The builddir may be created in arbitrary locations though -- from recollection, meson-python will create a random one using the tempfile module, which again has nothing to do with cpython version. But it has an option to pass in a builddir name that you would rather use, so you can make this be a stable location.

Umm, I don't think so:

# ls -al build
total 20
drwxrwxrwx. 1 1027 users  48 Sep 30 11:15 .
drwxrwxrwx. 1 1027 users 428 Oct 21 08:47 ..
drwxrwxrwx. 1 1027 users 296 Oct 17 16:01 cp312
-rwxrwxrwx. 1 1027 users  94 Sep 30 11:15 .gitignore
-rwxrwxrwx. 1 1027 users 110 Sep 30 11:15 .hgignore
#  ls -al build/cp312/
total 424
drwxrwxrwx. 1 1027 users    296 Oct 17 16:01 .
drwxrwxrwx. 1 1027 users     48 Sep 30 11:15 ..
-rwxrwxrwx. 1 1027 users  19843 Oct 16 20:13 build.ninja
-rwxrwxrwx. 1 1027 users   8731 Oct 16 20:13 compile_commands.json
drwxrwxrwx. 1 1027 users     14 Sep 30 11:15 controllers
drwxrwxrwx. 1 1027 users     20 Sep 30 11:15 emulator
drwxrwxrwx. 1 1027 users     36 Sep 30 11:15 frontends
drwxrwxrwx. 1 1027 users      0 Sep 30 11:15 lib
drwxrwxrwx. 1 1027 users    496 Oct 16 20:13 meson-info
drwxrwxrwx. 1 1027 users     26 Sep 30 11:15 meson-logs
drwxrwxrwx. 1 1027 users    396 Oct 16 20:13 meson-private
-rwxrwxrwx. 1 1027 users     40 Oct 16 20:13 meson-python-native-file.ini
-rwxrwxrwx. 1 1027 users 351588 Oct 17 16:01 .ninja_deps
-rwxrwxrwx. 1 1027 users   6681 Oct 17 16:01 .ninja_log
drwxrwxrwx. 1 1027 users     14 Sep 30 11:15 src

[eli-schwartz]

https://github.com/mesonbuild/meson-python/blob/99ca98dc518f54d91766bfdb2d364ea163c16eca/mesonpy/__init__.py#L941-L947

[QuLogic]

The builddir may be created in arbitrary locations though -- from recollection, meson-python will create a random one using the tempfile module, which again has nothing to do with cpython version. But it has an option to pass in a builddir name that you would rather use, so you can make this be a stable location.

Not for editable installs; those are in build/<python tag> where <python tag> is cp311 for CPython 3.11, pp38 for PyPy 3.8, etc.