"Theodore Ts'o" <tytso@xxxxxxx> writes: > On Mon, May 27, 2024 at 11:15:43AM +0200, Alyssa Ross wrote: >> This fixes building dependent packages that use -Werror. >> >> Signed-off-by: Alyssa Ross <hi@xxxxxxxxx> >> --- >> I'm assuming here that it is actually intentional that these variables >> are unused! I don't understand the code enough to know for sure — >> I'm just trying to fix some build regressions after updating e2fsprogs. :) > > Well, note that you only get the warning at all if you use > -Wunused-parameter, "-Wunused -Wextra", or "-Wall -Wextra". The > unused-parameter warning is not enabled unless you **really** go out > of your way to enable it, because it has so many false positives. The > gcc maintainers do not enable this insanity even with -Wall, so > someone really went out of their way to make your life miserable. :-) Yeah… https://github.com/storaged-project/libblockdev/blob/7cd19d14e61c8964187eac99cf276e6c999dc93e/src/plugins/fs/Makefile.am#L5 (In this case it /did/ end up with me having to look at the code and notice the SIZEOF_SIZE_T bug I sent another patch for, so something useful did actually come out of it this time…) > I generally think it's a really bad idea to turn on warnings as if > they are overdone Christmas tree lights. However, to accomodate this, > the normal way to suppress this is via __attribute__(unused). To do > this in a portable way to avoid breaking compilers which don't > understand said attribute: > > /* this is usually predfined in some header file like compiler.h */ > #ifdef __GNUC__ > #define EXT2FS_ATTR(x) __attribute__(x) > #else > #define EXT2FS_ATTR(x) > #endif > > ... > _INLINE_ errcode_t ext2fs_resize_mem(unsigned long EXT2FS_ATTR((unused)) old_size, > unsigned long size, void *ptr) > ... Okay, I'll send a v2 using this approach. > You can also play this game if you really have a huge number of stupid > gcc warnings that you want to suppress: > > /* this is usually predfined in some header file like compiler.h */ > #ifndef __GNUC_PREREQ > #if defined(__GNUC__) && defined(__GNUC_MINOR__) > #define __GNUC_PREREQ(maj, min) \ > ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) > #else > #define __GNUC_PREREQ(maj, min) 0 > #endif > #endif > > #if __GNUC_PREREQ (4, 6) > #pragma GCC diagnostic push > #pragma GCC diagnostic ignored "-Wunused-function" > #pragma GCC diagnostic ignored "-Wunused-parameter" > #endif > > ... > > #if __GNUC_PREREQ (4, 6) > #pragma GCC diagnostic pop > #endif > > I do this when I'm defining a lot of inline functions in a header > file, and some stupid person thinks that -Wunused -Wextra is actually > a good idea (hint: it's not), and I just want to shut up the > completely unnecessary warnings. > > Cheers, > > - Ted
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