I'm not arguing that it's a completely perfect language. But broken is an incredibly strong word for something that works when used as described in the document

I'm not arguing that it's a completely perfect language. But broken is an incredibly strong word for something that works when used as described in the documentation. I think the API designer was trying to be parsimonious and not assume too much about what you want to do with the data in your destination buffer. The requirement was to provide buffer overrun protection when the source string is too large, and this function provides that. Beyond that, the requirement that the character array be null-terminated is your decision. In fact, if you determine that it isn't null-terminated you can do other things besides null terminate it yourself. You might want to provide a helpful error message to consumers of your API rather than truncating their input data silently. Or you may try reallocating your buffer until the string fits. There's actual error handling that you can do with this function. In contrast, automatically null terminating the string makes that more difficult. The other issues that you have with C seem like preferences. There's nothing wrong with not breaking by default in a switch statement as long as you know that that's what happens.