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

From: Namhyung Kim
Date: Sun Jan 08 2012 - 04:41:34 EST


2012-01-08 (ì), 10:00 +0100, Ingo Molnar:
> * Namhyung Kim <namhyung@xxxxxxxxx> 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 ârecord_fileâ:
> > util/trace-event-info.c:192: error: implicit declaration of function
> > âpwriteâ
> > util/trace-event-info.c:192: error: nested extern declaration of
> > âpwriteâ
> > 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 ârecord_fileâ:
util/trace-event-info.c:192: error: implicit declaration of function
âpwrite64â
util/trace-event-info.c:192: error: nested extern declaration of
âpwrite64â

And 'map pwrite' on terminal says:

$ 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

Thanks.


--
Regards,
Namhyung Kim


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