Hi Jonny, On Mon, Nov 20, 2023 at 11:56:40AM +0000, Jonny Grant wrote: > BTW, GCC has a useful warning for truncation that may help code bases that use strncpy, you've probably seen this and the article, just sharing for completeness. It's actually the opposite. GCC's warnings about strncpy(3) are nefarious, as it warns in valid uses of strncpy(3) for writing a null-padded character sequence (the use for which strncpy(3) was designed), recommending the bogus use as a function for copying truncated strings. > > warning: ‘__builtin_strncpy’ output truncated before terminating nul copying XYZ bytes from a string of the same length [-Wstringop-truncation] > > > Martin's article from 2019 > https://developers.redhat.com/blog/2018/05/24/detecting-string-truncation-with-gcc-8#forming_truncated_strings_with_snprintf I discussed with Martin about this, IIRC, and he told me they had to decide which use of strncpy(3) to support, with the side effect that other uses would be warned about, and they chose the one that I think is bogus. Cheers, Alex -- <https://www.alejandro-colomar.es/>
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