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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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