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

[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);
 }
 
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