On Fri, 10 Jul 2020 at 08:37, Jonny Grant <jg@xxxxxxxx> wrote: > > 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 As mentioned, it's there. Search for -Wextra to find it. Searching for "-W " with a space doesn't find it because it's followed by a full stop. Searching for -W\> works though if you're reading the man page in a pager that supports regex searches. > >> 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. So what? Why would you need to do that? > >> 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 don't think it does. > I usually just amend the optimisation earlier in the command line myself. I don't. Lots of other people don't. > 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? No version, it's the unreleased development sources. > 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 Then you should probably be looking at the docs for your GCC version instead of the unreleased development sources. The docs for each version are available at https://gcc.gnu.org/onlinedocs/ Right at the bottom of the page is the link to the doc you've been using, which says "Please note that the following documentation refers to current development. Some information may not be applicable to any existing release."
