freebsd VS ctl

Second of all: The horrifying truth is that there is no such thing as a canonical text representation for IPv4 (source) (and yes... I am indeed citing the failed attempt to standardize this as my source for it not being standardized). Authoritatively speaking, all possible (non-binary) representations are equally invalid. In fact, text address resolution is typically delegated to the OS kernel, so what constitutes a "usable" address is liable to vary depending on if you're using Linux, OSX, Windows, or Other.

FreeBSD’s config files spring to mind. Here is an example:

https://github.com/lattera/freebsd/blob/master/etc/defaults/...

The macro idea has a long history. It would be good to reference its earlier uses. For example, freebsd/netbsd had "tree.h" back in 2002 [1].

[1] https://github.com/lattera/freebsd/blob/master/sys/sys/tree....

C Container Template Library (CTL)

I guess something like that may exist but it can be done with the preprocessor alone. See https://github.com/tylov/STC or https://github.com/glouw/ctl

I assume you refer to that two of the letters match with STL or STD, right? Even if they are not related to C at all. I assume STB, CTL, are not acceptable for you either?

The standard C library lacks any kind of containers (vectors, hash tables etc.) so the first thing would be to find one you like. For example, the C Template Library is a nice one: https://github.com/glouw/ctl

While I agree the common pattern is to use void*/dynamic dispatch, this is not necessary. E.g., https://github.com/glouw/ctl/ or https://github.com/c-blake/bst show a couple ways to have generic code statically specialized in regular old C.

The template instantiation is rewritten and is now similar to how glouw CTL library does it. STC no longer contains long macros for generating the templated code.

define type macros before #including the implementation. (intrusive) This is how https://github.com/glouw/ctl does it. The good: type-safety. no casting, clear error messages. Somewhat clumsy to have to individual #includes for each container type instantiation of the same container.