which object file is fstat64/stat64 located

which object file is fstat64/stat64 located

[Yubin Ruan]

Hi,

I am seeking help here since I got error of "undefined reference to
fstat64/stat64" when linking without libstdc++ in a C++ program. I was
trying to use libcxx, so I added -nodefaultlibs when compiling the
program. To get necessary symbols from libc, I added -lc  (and also
-lm -lgcc_s -lgcc). But I still got the undefined reference error.

Note that I never use fstat64/stat64 in my program. I only use fstat/stat.

From the man page[1] it is said that on Linux fstat/stat is a wrapper
around fstat64/stat64. So these two symbols must locate at some object
file I don't know.

[1]: http://man7.org/linux/man-pages/man2/stat.2.html

--
Yubin

Re: which object file is fstat64/stat64 located

[Marc Glisse]

On Mon, 17 Dec 2018, Yubin Ruan wrote:

> I am seeking help here since I got error of "undefined reference to
> fstat64/stat64" when linking without libstdc++ in a C++ program. I was
> trying to use libcxx, so I added -nodefaultlibs when compiling the
> program. To get necessary symbols from libc, I added -lc  (and also
> -lm -lgcc_s -lgcc). But I still got the undefined reference error.
>
> Note that I never use fstat64/stat64 in my program. I only use fstat/stat.
>
> From the man page[1] it is said that on Linux fstat/stat is a wrapper
> around fstat64/stat64. So these two symbols must locate at some object
> file I don't know.

Could it be that you are using those -l* flags in the wrong order?

-- 
Marc Glisse

Re: which object file is fstat64/stat64 located

[Yubin Ruan]

On Mon, Dec 17, 2018 at 1:06 PM Marc Glisse <marc.glisse@inria.fr> wrote:
>
> On Mon, 17 Dec 2018, Yubin Ruan wrote:
>
> > I am seeking help here since I got error of "undefined reference to
> > fstat64/stat64" when linking without libstdc++ in a C++ program. I was
> > trying to use libcxx, so I added -nodefaultlibs when compiling the
> > program. To get necessary symbols from libc, I added -lc  (and also
> > -lm -lgcc_s -lgcc). But I still got the undefined reference error.
> >
> > Note that I never use fstat64/stat64 in my program. I only use fstat/stat.
> >
> > From the man page[1] it is said that on Linux fstat/stat is a wrapper
> > around fstat64/stat64. So these two symbols must locate at some object
> > file I don't know.
>
> Could it be that you are using those -l* flags in the wrong order?

I don't think so. They are all added at the very end.

Or, are you sure that fstat64/stat64 are located in libc.so ? Using
"nm -gC /usr/lib64/libc.so |grep fstat64" give no output.

--
Yubin

Re: which object file is fstat64/stat64 located

[Florian Weimer]

* Yubin Ruan:

> I am seeking help here since I got error of "undefined reference to
> fstat64/stat64" when linking without libstdc++ in a C++ program. I was
> trying to use libcxx, so I added -nodefaultlibs when compiling the
> program. To get necessary symbols from libc, I added -lc  (and also
> -lm -lgcc_s -lgcc). But I still got the undefined reference error.

What's your target?

Thanks,
Florian

Re: which object file is fstat64/stat64 located

[Yubin Ruan]

On Mon, Dec 17, 2018 at 7:32 PM Florian Weimer <fweimer@redhat.com> wrote:
>
> * Yubin Ruan:
>
> > I am seeking help here since I got error of "undefined reference to
> > fstat64/stat64" when linking without libstdc++ in a C++ program. I was
> > trying to use libcxx, so I added -nodefaultlibs when compiling the
> > program. To get necessary symbols from libc, I added -lc  (and also
> > -lm -lgcc_s -lgcc). But I still got the undefined reference error.
>
> What's your target?

My target is a C++ program(mysqld) which use fstat/stat and other C++
standard library functions. Normally libstdc++ is used and everything
is fine. But I want to switch to libcxx.

--
Yubin

Re: which object file is fstat64/stat64 located

[Florian Weimer]

* Yubin Ruan:

> On Mon, Dec 17, 2018 at 7:32 PM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * Yubin Ruan:
>>
>> > I am seeking help here since I got error of "undefined reference to
>> > fstat64/stat64" when linking without libstdc++ in a C++ program. I was
>> > trying to use libcxx, so I added -nodefaultlibs when compiling the
>> > program. To get necessary symbols from libc, I added -lc  (and also
>> > -lm -lgcc_s -lgcc). But I still got the undefined reference error.
>>
>> What's your target?
>
> My target is a C++ program(mysqld) which use fstat/stat and other C++
> standard library functions. Normally libstdc++ is used and everything
> is fine. But I want to switch to libcxx.

With target I meant something like Windows, MacOS, or GNU/Linux, and the
processor architecture.

But for libcxx support, you should ask on a libcxx mailing list, not on
a GNU mailing list.

Thanks,
Florian