Hi Ian,
My last response mistakenly went to you alone, rather than to the list. This
should be seen by everyone.
As per your suggestion, I inspected the output of readelf -r with libgcc and
libstdc++. I get an enormous amount of output, but among all the entries I
see things like the following for libgcc:
000015a2 00000b04 R_386_PLT32 00000000 __addtf3
00000113 00001304 R_386_PLT32 00000000 __fabstf2
0000001d 00000c04 R_386_PLT32 00000000 __fixunssfdi
... And lots of others.
For libstdc++, I see things like:
0000003e 00001904 R_386_PLT32 00000000 _ZNSi6sentryC1ERSib
00000017 00001304 R_386_PLT32 00000000 _Znwj
0000001e 00001604 R_386_PLT32 00000000 _ZN10__cxxabiv116__enu
0000011e 00005904 R_386_PLT32 00000000 _Unwind_Resume
I just chose some of these entirely at random, but I am having a hard time
interpreting this output. Does it seem as though these libraries have
relocation information in them? I assume yes?
Once I have compiled my shared library, is there any trivial way of
verifying whether or not everything was compiled correctly for maximum
independence so to speak?
Thanks once again for your help!
Kind regards,
Philip Bennefall
----- Original Message -----
From: "Ian Lance Taylor" <iant@xxxxxxxxxx>
To: <philip@xxxxxxxxxxxx>
Cc: <gcc-help@xxxxxxxxxxx>
Sent: Friday, October 18, 2013 8:01 PM
Subject: Re: -fPIC and static libstdc++
On Fri, Oct 18, 2013 at 8:57 AM, Philip Bennefall <philip@xxxxxxxxxxxx>
wrote:
I am building a shared library which will be distributed to clients in
binary form only. I am attempting to make the same binary run on as many
Linux variants as possible, and so when I build it I specify the options
-shared and -fPIC. As part of the effort of making the library as
independent as possible, I also link both the C and C++ standard libraries
statically into the final shared library. I want to do this because I use
C++11 features internally, and I don't want to force the users of my
library
to have a C++11 compiler handy.
When doing this, do I need to build libstdc++ and libgcc from source with
-fPIC as well? Or is it okay to link with the static versions of these
libraries that are provided in my Ubuntu 13.04 gcc package?
On GNU/Linux the static versions of libstdc++ and libgcc are normally
compiled with -fPIC, precisely to support the kind of thing you are
doing. So it should work fine.
Ian
