| Message ID | 20230710191138.1534922-1-qing.zhao@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | gcc-14/changes.html: Deprecate a GCC C extension on flexible array members. | expand |
Ping… thanks. Qing > On Jul 10, 2023, at 3:11 PM, Qing Zhao <qing.zhao@oracle.com> 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. > + </li> > </ul> > > > -- > 2.31.1 >
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? What would be the most surprising example of code that's going to be rejected? Richard. > + </li> > </ul> > > > -- > 2.31.1 >
> On Aug 3, 2023, at 3:10 AM, Richard Biener <richard.guenther@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
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. + </li> </ul>