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    SubjectRe: [ERROR] perf build failure on current tip:perf/core
    Date
    Ingo Molnar <mingo@elte.hu> wrote:

    > * Namhyung Kim <namhyung@gmail.com> wrote:
    >
    >> 2012-01-08 (일), 10:00 +0100, Ingo Molnar:
    >> > * Namhyung Kim <namhyung@gmail.com> wrote:
    >> >
    >> > > Hi,
    >> > >
    >> > > When I tried to build perf, I was faced with following error:
    >> > >
    >> > > CC util/trace-event-info.o
    >> > > cc1: warnings being treated as errors
    >> > > util/trace-event-info.c: In function ‘record_file’:
    >> > > util/trace-event-info.c:192: error: implicit declaration of function
    >> > > ‘pwrite’
    >> > > util/trace-event-info.c:192: error: nested extern declaration of
    >> > > ‘pwrite’
    >> > > make: *** [util/trace-event-info.o] Error 1
    >> > >
    >> > > The code I tried was latest tip:perf/core - 9e183426bfb5 ("perf kvm: Fix
    >> > > copy & paste error in description") and code in mainline (v3.2) doesn't
    >> > > have this problem. Looking at the code, I couldn't find any clue to
    >> > > this. Any idea?
    >> > >
    >> > > FYI, my system is Ubuntu 10.04 on x86_64. gcc version is 4.4.3:
    >> >
    >> > Which header does pwrite() belong to on that system - what does
    >> > 'map pwrite' say? It ought to be unistd.h, which is directly
    >> > included in util/trace-event-info.c.
    >> >
    >> > My guess is that it might be related to:
    >> >
    >> > tools/perf/Makefile:ALL_CFLAGS = $(CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
    >> >
    >> > Which introduces pwrite64() and defines pwrite() to them.
    >> >
    >> > Does the patch below help? It's only a workaround really as
    >> > pwrite() ought to exist ... Also, i have only tested this on
    >> > 64-bit.
    >> >
    >> > Thanks,
    >> >
    >> > Ingo
    >> >
    >> > diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
    >> > index ac6830d..ba8b024 100644
    >> > --- a/tools/perf/util/trace-event-info.c
    >> > +++ b/tools/perf/util/trace-event-info.c
    >> > @@ -189,7 +189,7 @@ static void record_file(const char *file, size_t hdr_sz)
    >> > if (bigendian())
    >> > sizep += sizeof(u64) - hdr_sz;
    >> >
    >> > - if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0)
    >> > + if (hdr_sz && pwrite64(output_fd, sizep, hdr_sz, hdr_pos) < 0)
    >> > die("writing to %s", output_file);
    >> > }
    >> >
    >>
    >> Hello,
    >>
    >> Unfortunately, above patch doesn't work for my system:
    >>
    >> CC util/trace-event-info.o
    >> cc1: warnings being treated as errors
    >> util/trace-event-info.c: In function ‘record_file’:
    >> util/trace-event-info.c:192: error: implicit declaration of function
    >> ‘pwrite64’
    >> util/trace-event-info.c:192: error: nested extern declaration of
    >> ‘pwrite64’
    >>
    >> And 'map pwrite' on terminal says:
    >
    > 'man pwrite' i wanted to say.

    Ah, OK :) here it is.

    PREAD(2) Linux Programmer's Manual PREAD(2)

    NAME
    pread, pwrite - read from or write to a file descriptor at a given offset

    SYNOPSIS
    #define _XOPEN_SOURCE 500

    #include <unistd.h>

    ssize_t pread(int fd, void *buf, size_t count, off_t offset);

    ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
    ...

    And #defining _XOPEN_SOURCE to 500 before the #include doesn't resolve the issue.


    >
    >> $ 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

    Thanks,
    Namhyung

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