Messages in this thread |  | | | From | Namhyung Kim <> | | Subject | Re: perf build failure on Linus's tree | | Date | Fri, 04 May 2012 11:24:14 +0900 |
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Hi,
On Thu, 3 May 2012 22:14:03 -0400, Arnaud Lacombe wrote: > Hi, > > On Thu, May 3, 2012 at 9:50 PM, David Miller <davem@davemloft.net> wrote: >> From: Namhyung Kim <namhyung.kim@lge.com> >> Date: Fri, 04 May 2012 10:37:24 +0900 >> >>> Hi, >>> >>> On Thu, 3 May 2012 14:57:48 -0700, Greg KH wrote: >>>> Linus's tree right now (3.4.rc5.67.gac001.dirty) gives me the following >>>> build error when I try to build perf: >>>> CC util/parse-events-flex.o >>>> <stdout>: In function ‘yy_get_next_buffer’: >>>> <stdout>:1510:3: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] >>>> util/parse-events.l: In function ‘parse_events_lex’: >>>> util/parse-events.l:122:1: error: ignoring return value of ‘fwrite’, declared with attribute warn_unused_result [-Werror=unused-result] >>>> cc1: all warnings being treated as errors >>>> >>>> Do you really want to ensure that flex's build warnings fail the build? >>>> >>>> thanks, >>>> >>>> greg k-h >>> >>> Can't reproduce it on my Fedora 17 box: >> >> Because your glibc headers probably don't have the warn_unused_result attribute >> in the extern declaration of fwrite() like Greg's do. >> > `tools/perf/Makefile' adds -D_FORTIFY_SOURCE=2 on the compiler's > command line, which in turn adds `__attribute__ > ((__warn_unused_result__))' to fwrite(3)'s prototypes, via `__wur'. I > double checked by pre-processing `util/parse-events-flex.c' with the > same arguments used by perf. fwrite(3) ends up being declared as: > > extern size_t fwrite (__const void *__restrict __ptr, size_t __size, > size_t __n, FILE *__restrict __s) __attribute__ > ((__warn_unused_result__)); > > So it is definitively enabled, and used, on Fedora. > > Above tests were done on Fedora 15/x86_64 and Fedora 16/x86_64, `perf' > build without any issue there too. > > my 0.2c, > - Arnaud
On my desktop:
$ make util/parse-events-flex.i CC util/parse-events-flex.i
$ grep -A1 'size_t fwrite' util/parse-events-flex.i extern size_t fwrite (__const void *__restrict __ptr, size_t __size, size_t __n, FILE *__restrict __s) __attribute__ ((__warn_unused_result__)); -- extern size_t fwrite_unlocked (__const void *__restrict __ptr, size_t __size, size_t __n, FILE *__restrict __stream) __attribute__ ((__warn_unused_result__));
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