Re: [ERROR] perf build failure on current tip:perf/core

From: Namhyung Kim
Date: Sun Jan 08 2012 - 09:50:18 EST


2012-01-08 (Sun), 15:03 +0100, Ingo Molnar wrote:
> * Namhyung Kim <namhyung@xxxxxxxxx> wrote:
>
> > >> $ map pwrite
> > >> The program 'map' is currently not installed. You can install it by
> > >> typing:
> > >> sudo apt-get install sgt-puzzles
> > >>
> > >> I don't think this is the package what you said. Anyway quick grep'ing
> > >> pwrite tells me it's in the unistd.h:
> > >>
> > >> $ grep pwrite /usr/include/unistd.h
> > >> extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
> > >> extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
> > >> pwrite64) __wur;
> > >> # define pwrite pwrite64
> > >
> > > There's multiple definitions there, and we get lost somehow - as
> > > unistd.h is included:
> > >
> > > ~/tip/tools/perf> grep -n unistd.h util/trace-event-info.c
> > > 34:#include <unistd.h>
> > >
> > > Thanks,
> > >
> > > Ingo
> >
> > This is the content of my /usr/include/unistd.h:
> >
> > #ifdef __USE_UNIX98
> > # ifndef __USE_FILE_OFFSET64
> > extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
> > __off_t __offset) __wur;
> > extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
> > __off_t __offset) __wur;
> > # else
> > # ifdef __REDIRECT
> > extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
> > __off64_t __offset),
> > pread64) __wur;
> > extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
> > size_t __nbytes, __off64_t __offset),
> > pwrite64) __wur;
> > # else
> > # define pread pread64
> > # define pwrite pwrite64
> > # endif
> > # endif
> >
> > # ifdef __USE_LARGEFILE64
> > extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
> > __off64_t __offset) __wur;
> > extern ssize_t pwrite64 (int __fd, __const void *__buf, size_t __n,
> > __off64_t __offset) __wur;
> > # endif
> > #endif
> >
> > I think all of pread/write functions are properly defined here:
> >
> > $ echo '#include <unistd.h>' | \
> > > gcc -xc -E -dM -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 - | \
> > > grep -e UNIX98 -e LARGEFILE64 -e FILE_OFFSET
> > #define __ILP32_OFFBIG_CFLAGS "-m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
> > #define _LARGEFILE64_SOURCE 1
> > #define __USE_UNIX98 1
> > #define __USE_LARGEFILE64 1
> > #define _FILE_OFFSET_BITS 64
> > #define __USE_FILE_OFFSET64 1
>
> So which preprocessor branch within unistd.h does it get into on
> your system and why isnt there a pwrite()/pwrite64() prototype
> once it goes along that path?
>
> You could try an ugly approach and edit your unistd.h and put in
> debug lines like this:
>
> #warn got here: __LINE__
>
> and thus see which branch it really gets into.
>
> (save a backup copy of unistd.h first ;-)
>
> Thanks,
>
> Ingo

Hi, Ingo

Putting the debug lines told me __USE_UNIX98 is not defined for the
file. It's because ctype.h gets included without _GNU_SOURCE and then it
includes feature.h AFAICS. Encompassing ctype.h with #define/#undef
_GNU_SOURCE or just adding __USE_UNIX98 before unistd.h makes the file
compiled, but it seems like an improper solution. What is the right way?

Thanks.

--
Regards,
Namhyung Kim


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