> On Aug 3, 2023, at 3:10 AM, Richard Biener <richard.guent...@gmail.com> wrote: > > On Mon, Jul 10, 2023 at 9:12 PM Qing Zhao via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> Hi, >> >> This is the change for the GCC14 releaes Notes on the deprecating of a C >> extension about flexible array members. >> >> Okay for committing? >> >> thanks. >> >> Qing >> >> ======== >> >> *htdocs/gcc-14/changes.html (Caveats): Add notice about deprecating a C >> extension about flexible array members. >> --- >> htdocs/gcc-14/changes.html | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html >> index 3f797642..c7f2ce4d 100644 >> --- a/htdocs/gcc-14/changes.html >> +++ b/htdocs/gcc-14/changes.html >> @@ -30,7 +30,15 @@ a work-in-progress.</p> >> <!-- .................................................................. --> >> <h2>Caveats</h2> >> <ul> >> - <li>...</li> >> + <li><strong>C:</strong> >> + Support for the GCC extension, a structure containing a C99 flexible >> array >> + member, or a union containing such a structure, is not the last field >> of >> + another structure, is deprecated. Refer to >> + <a href="https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html";> >> + Zero Length Arrays</a>. >> + Any code relying on this extension should be modifed to ensure that >> + C99 flexible array members only end up at the ends of structures. > > If it's deprecated any use should be diagnosed by default with a > warning, can you > mention that and make sure we do so?
I have added such warning option: -Wflex-array-member-not-at-end In commit https://gcc.gnu.org/pipermail/gcc-cvs/2023-June/385730.html I should add this warning option to the release notes. I will do that. Another thing is, I just realized that the doc of this new option is missing from the invoke.texi. I will send a new patch for the documentation of this new option first. > What would be the most surprising > example of code that's going to be rejected? struct flex { int length; char data[]; }; struct mid_flex { int m; struct flex flex_data; int n; }; The above example, the 2nd structure mid_flex will be warned. Qing > > Richard. > >> + </li> >> </ul> >> >> >> -- >> 2.31.1
