Thank you for you reply. On 10/07/2020 00:58, Jonathan Wakely wrote: > On Thu, 9 Jul 2020 at 23:54, Jonny Grant <jg@xxxxxxxx> wrote: >> >> Hello >> >> I noticed g++ ignores -W as I understand it that alone doesn't turn anything on? > > No, -W is identical to -Wextra. I looked but couldn't find any mention of it. Is it worth documenting this on the page? https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html >> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html >> >> Also may I ask if specifying both -pedantic -Wpedantic be an error? They are the same as I understand. g++ doesn't reject them both being specified. > > They mean the same thing. It's not an error to repeat options. Fair enough, it doesn't help anyone remove duplicates from their warning list in makefile etc though. >> Another example is -O1 -O0 -O3, the later -03 seems to be used. Maybe nice to say too many optimization options specified? > > No, it's common (and very useful) to append an option to the end of a > command and have it override earlier options. > > This behaviour is documented, and relied on by many people. clang gives a nice helpful warning I recall. I usually just amend the optimisation earlier in the command line myself. This isn't directly related, but the main page doesn't show what version of GCC it refers to https://gcc.gnu.org/onlinedocs/gcc/ Could the page show what version it is on that page? Took me a while to realise that this page was only introduced with GCC 10 from what I can see https://gcc.gnu.org/onlinedocs/gcc/Static-Analyzer-Options.html Cheers, Jonny
