Frequently Asked Questions¶

I am getting weird Git errors about an unknown `-C` option¶

You may be using a system with an old version of Git. You may install a recent version of Git for your user by running nix-env -iA nixpkgs.git.

A file I created isn’t found when I run `nix build`¶

If your top is a Git repository, you must git add those files to make them recognized by Nix.

An App can’t find a build product from another App¶

EPNix enables parallel builds by default. These means that if App dependencies aren’t specified, these Apps will compile in no particular order. Use <consumerApp>_DEPEND_DIRS += <producerApp> in your top-level Makefile.

How do I version a whole EPNix top?¶

Meaning, not versioning an App separate from the top. This might be justified if you don’t intend to share an App in any other top.

First, create a top and an App, as in the Creating a StreamDevice IOC tutorial.
Make sure to add an exception for the exampleApp folder at the end of the top’s .gitignore file:

...
# Applications and Support modules should be an EPNix dependency in flake.nix
*App
*Sup
# You can add exceptions like this:
# ---
#!myCustomLocalApp
!exampleApp

Then, version both the top and the App:

git init
git add -N .

Finally, in your flake.nix, you can remove any input and value in epnix.applications.apps that refers to this directory.