[Crinus]

I already gave an example of APIs that do this - pretty much all COM APIs use HRESULT. I do not know why not everyone does this as i'm not everyone and as such i cannot tell what sort of considerations (if any) were going on. At best i can make some guesses.

BTW curl does seem to do what i wrote above, for example `curl_easy_init` returns a `CURL` object on success or NULL if there was an error [1] and `curl_easy_perform` returns a `CURLcode` value [2] that looks like it is used across the API to indicate errors.

[1] https://curl.haxx.se/libcurl/c/curl_easy_init.html

[2] https://curl.haxx.se/libcurl/c/curl_easy_perform.html