[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
Launchpad has imported 31 comments from the remote bug at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=28322. If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. On 2006-07-08T23:03:50+00:00 Debian GCC maintainers wrote: [forwarded from http://bugs.debian.org/367657] Summary: GCC should be more tolerant of gcc -Wno-this-is-not-a-recognised-warning as specified in detail below. Discussion: Occasionally, GCC introduces new warnings. For example, GCC 4 has introduced warnings about discrepancies in signedness of integers pointed to by otherwise-compatible pointers. Furthermore, because GCC has traditionally had such good warnings, and such good configurability of warnings, and because no-one looks at warnings that don't cause build failures, many people (myself included) use -Werror in nearly all of their projects. However, when new warnings are introduced, there is a problem with the configurability: Like any warning, whether or not you want it enabled depends on your coding style and practices and on other rather subjective details. This means that there can be no universally correct default for a new warning; turning it on by default is sometimes a reasonable value judgement on the part of the compiler authors. When a new warning is introduced and enabled by default, then the author of a project whose coding style warrants disabling that warning is faced with a difficult choice: * they can set the build system to say -Wno-new-warning (for whatever value of `new-warning' is relevant) so that it builds on new compilers but so that users of older GCC's need to override the build system to remove -Wno-new-warning (which the older GCC doesn't understand); * they can turn off -Werror, leaving themselves open to the massive bugs which are often hidden by warnings which are ignored (perhaps bugs which don't show up and aren't warned about on the developer's system, because of the various type differences between systems); * they can leave things as they are and require users of the new compiler to override the build system. * they can add complexity to the build system to try to autodetect the available compiler options; this usually works but it makes the build system more complex - note that in some projects this might be the only reason why something like autoconf might be required. None of these are the right answer. I would like to propose a straightforward answer which can easily be implemented in GCC and leaves everything correct. With this change, it is much easier to make portable packages which still make good and strict use of GCC's excellent warnings system. Specification of the proposed new behaviour: 1. GCC should ignore unknown -Wno-* options if no other warnings are to be issued. This is always correct since the only effect of such an option would be to suppress warnings which might otherwise be issued. If no warnings are to be issued at all then treating even an unknown suppression as a no-op is clearly correct. 2. If some other warnings are to be issued, then it is necessary to report on stderr if any unknown (and therefore unheeded) suppressions were in force, in case the user intended for one of the relevant suppressions to apply to the warning(s) in question. This will alert the user to the lack of support for that suppression in this gcc (ie, either to the user's typo or the wrong gcc version). The combination of (1) and (2) will minimise stderr noise about unknown suppressions as far as I think is reasonably possible. 3. Obviously unknown suppressions ignored according to (1) should not count as errors for -Werror. Whether unknown suppressions reported according to (2) should count as as errors for -Werror is not important because the actual warning will count as an error for -Werror. So the diagnostic from (2) above can be a real `warning', or simply an appropriate message issued to stderr the first time a warning is to be issued despite the presence of unknown -Wno-* options. 4. Whenever a new GCC warning is introduced, or the scope of an existing warning significantly extended, a corresponding -Wno-* option should be introduced at the same time. (AFAIAA current GCC development practice seems to abide by this principle.) 5. The changes to implement (1) and (2) should be backported to earlier GCCs and earlier Debian branches insofar as practical. Reply at: https://bugs.launchpad.net/ubuntu/+source/gcc-4.2/+bug/284401/comments/0 On 2006-07-09T10:41:01+00:00 Pinskia wrote: This is more of a policy issue rather than a bug. > Occasionally, GCC in
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
** Changed in: gcc Importance: Unknown => Wishlist -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/284401 Title: gcc fails when "-Wall" "-Wno-long-double" parametres used together To manage notifications about this bug go to: https://bugs.launchpad.net/gcc/+bug/284401/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
** Changed in: gcc Status: Confirmed => Fix Released -- gcc fails when "-Wall" "-Wno-long-double" parametres used together https://bugs.launchpad.net/bugs/284401 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
works as expected. the warning about the unrecognized command line option is only printed if there are other warnings, otherwise it's ignored. see the upstream report. ** Changed in: gcc-4.2 (Ubuntu) Status: Triaged => Invalid -- gcc fails when "-Wall" "-Wno-long-double" parametres used together https://bugs.launchpad.net/bugs/284401 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
** Changed in: gcc Status: Unknown => Confirmed -- gcc fails when "-Wall" "-Wno-long-double" parametres used together https://bugs.launchpad.net/bugs/284401 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
$ cat main.c
int main() {}
$ gcc -c -g -Wall -Wno-long-double main.c
main.c: In function 'main':
main.c:1:1: warning: control reaches end of non-void function
At top level:
cc1: warning: unrecognized command line option "-Wno-long-double"
only when no other warning is present, the warning about the unrecognized
option vanishes:
$ cat main.c
int main() {return 0;}
$ gcc -c -g -Wall -Wno-long-double main.c
$
** Bug watch added: GCC Bugzilla #28322
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28322
** Also affects: gcc via
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28322
Importance: Unknown
Status: Unknown
** Changed in: gcc-4.2 (Ubuntu)
Importance: Undecided => Low
** Changed in: gcc-4.2 (Ubuntu)
Status: Confirmed => Triaged
--
gcc fails when "-Wall" "-Wno-long-double" parametres used together
https://bugs.launchpad.net/bugs/284401
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[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
Just upgraded gcc to new version and the problem still exists: gcc -v Using built-in specs. Target: i486-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --enable-targets=all --enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu Thread model: posix gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3) -- gcc fails when "-Wall" "-Wno-long-double" parametres used together https://bugs.launchpad.net/bugs/284401 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 284401] Re: gcc fails when "-Wall" "-Wno-long-double" parametres used together
I can confirm this bug. :~$ gcc --version gcc (GCC) 4.2.3 (Ubuntu 4.2.3-2ubuntu7) 8.04.1 Linux Stormbringer 2.6.24-21-generic #1 SMP Mon Aug 25 16:57:51 UTC 2008 x86_64 GNU/Linux ** Changed in: gcc-4.2 (Ubuntu) Status: New => Confirmed -- gcc fails when "-Wall" "-Wno-long-double" parametres used together https://bugs.launchpad.net/bugs/284401 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
