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

[Ingo Molnar <mingo@elte.hu>]

* 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.

>   $ 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