Yesterday I asked this question - which is about methods to use bitwise operations to interleave zero and non-zero bytes. It has a practical application in UTF-8 to UTF-16 conversion.
The question is narrow and specific - it could pretty much be an interview question or appear on a CS 101 test. The bit operations in question appear with identical functionality across C, C++ and Java (if you accept that >>> in Java is equivalent to a cast unsigned in C/C++).
I tagged it that way because those are the languages I'm targeting and I expect answers to be equivalent across languages. Indeed the example, and most of the suggested answers all compile as-is in each language (the exception being the 'union' answer which is only directly applicable to C and C++).
The question, however, was closed as "not constructive", mostly, it seems, because of the multiple language tags. Browsing the high level guidance here and on the main SO site, questions closed for this reason are usually vague, lead to open ended debate, aren't questions at all, etc. The FAQ states:
We expect answers to be supported by facts, references, or specific expertise, but this question will likely solicit debate, arguments, polling, or extended discussion.
I feel like this question doesn't pose any of those problems. So I'm here to ask the community if multiple language tags a truly a red line, and if even if they aren't to comment whether they were appropriate here.
It's pretty clear I could define a meta-language, which consists of exactly the bit-wise and arithmetic operators I'm interested in, and ask this in that context, but that seems much less useful than using the common parts of the languages I'm interested in and that the community understands.