When hiring, we filter applications on what they claim on the CV but also actually dig into the required skills on interview.
If we find a mismatch, it invalidates the candidate as a whole. If someone claims 8 years of MOVA but doesn't know basic stuff about MOVA semantics, they were either lying, they are incompetent, or they have been coasting.
When I started interviewing I used to do that, until I realised it would eliminate about 20% of all useful candidates. The killer is c++. The industry is filled with people who have vague memories of trying to use C++ in the 90s before switching to Java or c# as quickly as possible, but still put C++ on their resume. In reality they can't even do basic tasks like reading a file into an array. Knocking them out because of this exaggeration would have just throttled the candidate stream unnecessarily and it didn't seem like a consequential exaggeration.
Other lies on the other hand, do cause me to drop people. One guy claimed to be an expert in the internals of hotspot. Unfortunately for him I actually am such an expert. It turned out he hadn't even read the user manual. That sort of lie is a problem because it's the sort of thing that will sound impressive to a lot of people who can't verify it, and he surely knew that.
People also have different priorities. I never wrote an application in C++ and don't care about boring but practical stuff like the file API or syntax.
But I like learning about C++. It has many interesting features and concepts. Understanding those, their design trade-offs, how and why it differs from other languages (e.g. Rust) is fun. So I know more about "advanced" C++ than I know about "basic" C++.
I think you’re spot on about C++. I am one of those people who wrote C for many years, worked exclusively in C++ for 4-5 years, but haven’t touched it in about 10-12 years.
In one sense it feels silly to leave it off my resume because it was literally what I did. But I’m not interested in writing C++ and really haven’t touched it in a decade, so I could never pass a technical C++ interview.
> do basic tasks like reading a file into an array
not 100% on-topic, but that's an interesting one because I'd expect many active devs could stumble over: Reading a file isn't difficult, but it's also not something you actually do very often. If you do C++, you're often working in large projects where reading files is something done by libraries, custom wrappers, ... It's firmly in "if you need it, once every few years, it's in the docs" land.
Whereas I do comparatively little code in Python, but a lot of it is small one-off scripting where file handling using the basic facilities is typical.
If we find a mismatch, it invalidates the candidate as a whole. If someone claims 8 years of MOVA but doesn't know basic stuff about MOVA semantics, they were either lying, they are incompetent, or they have been coasting.