How to generate C headers from Nim

I wrote a library which is intended to be used in C as well. Compiling the library to a .dll/.so/.lib itself is well documented and works as expected.

However, I cannot find anything regarding the corresponding header files. The only documentation for something like this that I found, is the --header cli argument which was supposedly (to be?) removed. Can't find it in the https://nim-lang.org/docs/nimc.html page, nor in the help-page of my installation.

Nim-Version:

$ nim -v
Nim Compiler Version 1.6.0 [Windows: amd64]
Compiled at 2021-10-19

In the documentation for the exportc pragma, it only explains the naming and how it can be used. Same goes for the backend-integration Page, which also doesn't state anything helpful regarding header files.

Is there a proper way to generate the header-files from nim-source code, or do I have to write these manually?

Solution

You can use the Genny nimble package to generate a C header file (and also Python and Node.js bindings!) for your Nim library.

Besides that, writing the header manually would be the next best choice. Well, the --header option does still happen to work, but it's not recommended to use it as it's undocumented and unsupported.