Re: svn commit: r243134 - head/sys/sys
On Thu, Nov 15, 2012 at 10:25 PM, Konstantin Belousov k...@freebsd.org wrote: Author: kib Date: Fri Nov 16 06:25:20 2012 New Revision: 243134 URL: http://svnweb.freebsd.org/changeset/base/243134 Log: Alphabetically reorder the forward-declarations of the structures. Add the declaration for enum idtype, to be used later. Forward declarations of enums isn't an ISO C feature, but a gcc extension. While the kernel uses many gcc extensions, it hides most under a #define so unsupported compilers can continue along. This unsupported feature can't be hidden. Does the forward declaration prevent another warning? Thanks, matthew Reported and reviewed by: bde MFC after:28 days Modified: head/sys/sys/syscallsubr.h Modified: head/sys/sys/syscallsubr.h == --- head/sys/sys/syscallsubr.h Fri Nov 16 06:22:14 2012(r243133) +++ head/sys/sys/syscallsubr.h Fri Nov 16 06:25:20 2012(r243134) @@ -35,25 +35,26 @@ #include sys/mount.h struct file; +enum idtype; struct itimerval; struct image_args; struct jail; +struct kevent; +struct kevent_copyops; +struct kld_file_stat; +struct ksiginfo; struct mbuf; struct msghdr; struct msqid_ds; +struct ogetdirentries_args; struct rlimit; struct rusage; -struct __wrusage; union semun; +struct sendfile_args; struct sockaddr; struct stat; -struct kevent; -struct kevent_copyops; -struct kld_file_stat; -struct ksiginfo; -struct sendfile_args; struct thr_param; -struct ogetdirentries_args; +struct __wrusage; intkern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen); ___ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to svn-src-all-unsubscr...@freebsd.org
Re: svn commit: r243134 - head/sys/sys
On Fri, Nov 16, 2012 at 08:02:39AM -0800, m...@freebsd.org wrote: On Thu, Nov 15, 2012 at 10:25 PM, Konstantin Belousov k...@freebsd.org wrote: Author: kib Date: Fri Nov 16 06:25:20 2012 New Revision: 243134 URL: http://svnweb.freebsd.org/changeset/base/243134 Log: Alphabetically reorder the forward-declarations of the structures. Add the declaration for enum idtype, to be used later. Forward declarations of enums isn't an ISO C feature, but a gcc extension. While the kernel uses many gcc extensions, it hides most under a #define so unsupported compilers can continue along. This unsupported feature can't be hidden. Does the forward declaration prevent another warning? It allows to prevent the namespace pollution from sys/wait.h idtype_t, needed due to the kern_wait6() declaration. pgpG7hmjYsrfQ.pgp Description: PGP signature
Re: svn commit: r243134 - head/sys/sys
On Fri, 16 Nov 2012, Konstantin Belousov wrote: On Fri, Nov 16, 2012 at 08:02:39AM -0800, m...@freebsd.org wrote: On Thu, Nov 15, 2012 at 10:25 PM, Konstantin Belousov k...@freebsd.org wrote: Author: kib Date: Fri Nov 16 06:25:20 2012 New Revision: 243134 URL: http://svnweb.freebsd.org/changeset/base/243134 Log: Alphabetically reorder the forward-declarations of the structures. Add the declaration for enum idtype, to be used later. Forward declarations of enums isn't an ISO C feature, but a gcc extension. While the kernel uses many gcc extensions, it hides most under a #define so unsupported compilers can continue along. This unsupported feature can't be hidden. Ugh. We discussed the unportability of enums in APIs when cleaning this up. kib said that the size of an enum type is an ABI standard for i386 and amd64. I don't quite agree for i386, and we didn't discuss other arches. The size of an enum type must be fixed for the gcc extension to be possible. gcc -std=c99 -pedantic generates a warning for forward enum declaration. Long ago, I routinely tested with -pedantic and committed fixes for all the things that it found if they were not too hard to fix. Does the forward declaration prevent another warning? It allows to prevent the namespace pollution from sys/wait.h idtype_t, needed due to the kern_wait6() declaration. syscallsubr.h and especially sysproto.h have lots of other namespace pollution. My version of sysproto.h reduces the pollution to just sys/_sigset.h using 6 #define hacks and 1 clean #include change to reduce 5 polluting headers and 1 non-polluting one to 1 different non-polluting one. The #define hacks can't work for enums. When I worked on reducing the pollution in sysproto.h in its automatic generation, I got it down to sys/signal.h and not much more. sys/_sigset.h because available later, but -current still has the full pollution of sys/signal.h and much more. Non-auto-generated headers like syscallsubr.h are easier to clean. Bruce ___ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to svn-src-all-unsubscr...@freebsd.org
Re: svn commit: r243134 - head/sys/sys
On Sat, Nov 17, 2012 at 04:24:06AM +1100, Bruce Evans wrote: On Fri, 16 Nov 2012, Konstantin Belousov wrote: On Fri, Nov 16, 2012 at 08:02:39AM -0800, m...@freebsd.org wrote: On Thu, Nov 15, 2012 at 10:25 PM, Konstantin Belousov k...@freebsd.org wrote: Author: kib Date: Fri Nov 16 06:25:20 2012 New Revision: 243134 URL: http://svnweb.freebsd.org/changeset/base/243134 Log: Alphabetically reorder the forward-declarations of the structures. Add the declaration for enum idtype, to be used later. Forward declarations of enums isn't an ISO C feature, but a gcc extension. While the kernel uses many gcc extensions, it hides most under a #define so unsupported compilers can continue along. This unsupported feature can't be hidden. Ugh. We discussed the unportability of enums in APIs when cleaning this up. kib said that the size of an enum type is an ABI standard for i386 and amd64. I don't quite agree for i386, and we didn't discuss other arches. The size of an enum type must be fixed for the gcc extension to be possible. In my copy of the SVID rev 4, document abi386, it is stated absolutely clear that Integral enum types are represented as the signed word with sizeof 4 and alignment 4. This is in Figure 3-1 Scalar Types, page 28. For amd64, in the ABI document 0.99.6, enums are again specified in the figure 3.1 as having signed fourbyte representation with the alighnment 4. Now, there is a footnote stating C++ and some implementations of C permit enums larger than an int. The underlying type is bumped to an unsigned int, long int or unsigned long int, in that order. But I think that the complain is not about the ABI, but regarding the use of the extension. I see three routes forward: - Keep the things as is. The only downside is the use of the extension which is supported by both gcc and clang. - Change idtype_t to int and use #defines to introduce P_XXX constants. This is not easy since Solaris contrib code uses enum, and enum was selected to not introduce unneeded incompatibility, at least for the kernel code. - Include sys/wait.h from sys/syscallsubr.h. A modification is to put idtype_h into a private header and include the header from syscallsubr.h and wait.h. My preference is to keep the things as is, but I am open for discussion. gcc -std=c99 -pedantic generates a warning for forward enum declaration. Long ago, I routinely tested with -pedantic and committed fixes for all the things that it found if they were not too hard to fix. Does the forward declaration prevent another warning? It allows to prevent the namespace pollution from sys/wait.h idtype_t, needed due to the kern_wait6() declaration. syscallsubr.h and especially sysproto.h have lots of other namespace pollution. My version of sysproto.h reduces the pollution to just sys/_sigset.h using 6 #define hacks and 1 clean #include change to reduce 5 polluting headers and 1 non-polluting one to 1 different non-polluting one. The #define hacks can't work for enums. When I worked on reducing the pollution in sysproto.h in its automatic generation, I got it down to sys/signal.h and not much more. sys/_sigset.h because available later, but -current still has the full pollution of sys/signal.h and much more. Non-auto-generated headers like syscallsubr.h are easier to clean. Bruce pgpaip4cWcBcS.pgp Description: PGP signature
svn commit: r243134 - head/sys/sys
Author: kib Date: Fri Nov 16 06:25:20 2012 New Revision: 243134 URL: http://svnweb.freebsd.org/changeset/base/243134 Log: Alphabetically reorder the forward-declarations of the structures. Add the declaration for enum idtype, to be used later. Reported and reviewed by: bde MFC after:28 days Modified: head/sys/sys/syscallsubr.h Modified: head/sys/sys/syscallsubr.h == --- head/sys/sys/syscallsubr.h Fri Nov 16 06:22:14 2012(r243133) +++ head/sys/sys/syscallsubr.h Fri Nov 16 06:25:20 2012(r243134) @@ -35,25 +35,26 @@ #include sys/mount.h struct file; +enum idtype; struct itimerval; struct image_args; struct jail; +struct kevent; +struct kevent_copyops; +struct kld_file_stat; +struct ksiginfo; struct mbuf; struct msghdr; struct msqid_ds; +struct ogetdirentries_args; struct rlimit; struct rusage; -struct __wrusage; union semun; +struct sendfile_args; struct sockaddr; struct stat; -struct kevent; -struct kevent_copyops; -struct kld_file_stat; -struct ksiginfo; -struct sendfile_args; struct thr_param; -struct ogetdirentries_args; +struct __wrusage; intkern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen); ___ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to svn-src-all-unsubscr...@freebsd.org
