Messages in this thread | | | Date | Thu, 17 Sep 2015 11:37:08 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: Linux 4.3-rc1 build error wi th older elfutils "util/symbol-elf.c:41:5: error: no previous prototype for ‘elf getphdrnum’ " |
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Em Thu, Sep 17, 2015 at 11:06:19AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Sep 17, 2015 at 09:28:31AM +0300, Adrian Hunter escreveu: > > On 17/09/15 01:10, Vinson Lee wrote: > > > With Linux 4.3-rc1 I get a perf build error using toolchains with > > > older elfutils. > > > > > > The following build error occurs on both CentOS 5.11 (elfutils 0.137) > > > and Ubuntu 10.04.4 (elfutils 0.143). > > > > > > CC util/symbol-elf.o > > > cc1: warnings being treated as errors > > > util/symbol-elf.c:41: error: no previous prototype for ‘elf_getphdrnum’ > > > > commit f785f2357673d520a0b7b468973cdd197f336494 > > removed the 'static' qualifier, presumably because there > > are cases where the prototype is in the header but the function is > > not in the library. > > > > AFAICT gcc accepts multiple prototypes so long as they are the same > > so just adding the prototype should be ok i.e. > > But that looks like a bandaid :-\ > > The comment I made in f785f2357673d520a0b7b468973cdd197f336494 was not > clear enough, now I'm the one trying to figure out why I did that... Duh > :-\ > > I.e. if: > > "HAVE_ELF_GETPHDRNUM_SUPPORT is false" we shouldn't have any prototype > for that elf_getphdrnum function, i.e. the fact that it is in libelf.h > should mean that it is present, how come the feature test for it failed, > i.e. HAVE_ELF_GETPHDRNUM_SUPPORT wasn't defined?
So, on RHEL5.11 (aka, I guess, CentOS 5.11):
[acme@rhel5 linux]$ cat /etc/redhat-release Red Hat Enterprise Linux Server release 5.11 (Tikanga) [acme@rhel5 linux]$ rpm -q elfutils elfutils-0.137-3.el5 [acme@rhel5 linux]$ cat /tmp/build/perf/feature/test-libelf-getphdrnum.make.output cc1: warnings being treated as errors test-libelf-getphdrnum.c: In function ‘main’: test-libelf-getphdrnum.c:7: warning: implicit declaration of function ‘elf_getphdrnum’ [acme@rhel5 linux]$
If I revert my patch, it builds... I am now building this in more systems while trying to get my head around how HAVE_ELF_GETPHDRNUM_SUPPORT can be false while elf_getphdrnum() is defined.
- Arnaldo
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