My question is an extension of this question
I want to link against 2 libraries - foo and bar preferring static for foo and dynamic for bar. If I use
g++ -static -lfoo -lbar
it tries to find static archives for both foo and bar. When I change the command to
g++ -Wl,-Bstatic -lfoo -Wl,-Bdynamic -lbar -Wl,--as-needed
as per the above SO question, this is the error I get:
ld: unknown option: -Bstatic
Update:
I am using OSX, if that makes any difference
Are we dealing with the GNU linker here? Can you show us the output of "ld -v"?
EDIT: that doesn't look like GNU's ld, so that's why the -Bstatic option is not recognized. And it seems that Apple's ld doesn't support mixing static and dynamic libraries very well; see this: Mixed static and dynamic link on Mac OS.
Yes, unfortunately, using OS X is making the difference. -static is asking the compiler to give you a fully statically linked executable (not supported on OS X), and as Adiel pointed out, -Wl,-Bstatic for mixing static and dynamic linking isn't supported by Apple's clang linker.
To get around this problem on the Mac try:
g++ myapp.cpp libfoo.a libbar.a
as your compile line (where library names follow your source on the command line). This will give you myapp statically linked with the foo and bar libraries, while other required libraries will be linked in dynamically.
Related
I've build a shared library on my desktop that uses statically linked gstreamer and gstreamer plugins (base, good, rtsp-server).
Now I'm trying to compile the library using yocto but its giving me a linker error:
version node not found for symbol _IO_do_write##GLIBC_2.17
failed to set dynamic section sizes: Bad value
The solutions I found on stack overflow did not seem to help me.
use compiler with --disable-symvers
link libc libs in different orders (-ldl -lm -lc -lpthread -ltinfo -lrt)
link libc libs statically/shared
What I find particularly odd is that the linker is looking for GLIBC_2.17 while yocto uses 2.27 and my system is using 2.24. I don't know if this matters or if it is normal (the function did not change since 2.17?).
NM -C shows the symbol in libc.a:
nm -C recipe-sysroot/usr/lib/libc.a | grep IO_do_write
U _IO_do_write
U _IO_do_write
0000000000001ba8 W _IO_do_write
So I would thinks that lib is linked incorrectly?
The linker command is a long one because of all the shared libs so I shortend it a bit (removed boost and custom libs):
aarch64-poky-linux-g++ -fPIC --sysroot=recipe-sysroot -O2 -pipe -g -feliminate-unused-debug-types -fdebug-prefix-map=recipe-root/git-r0 -fdebug-prefix-map=recipe-sysroot= -fdebug-prefix-map=recipe-sysroot-native= -fvisibility-inlines-hidden --sysroot=recipe-sysroot -Wl,-allow-multiple-definition -Wall -Wextra -Wpedantic -Wsuggest-override -Wswitch-default -Wduplicated-cond -Wshadow -Werror -ftemplate-depth=1024 -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -lc -Wl,--no-as-needed -Wl,--no-undefined -pthread -ldl -shared -Wl,-soname,rtsp_streamer.so -o rtsp_streamer.so ... custom static libs .and boost static libs ... -lpthread recipe-sysroot/usr/lib/gstreamer-1.0/libgstrtsp.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstrtp.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstrtpmanager.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstcoreelements.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstadder.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstapp.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstaudioconvert.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstaudiorate.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstaudioresample.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstaudiotestsrc.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstgio.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstpango.a recipe-sysroot/usr/lib/gstreamer-1.0/libgsttypefindfunctions.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvideoconvert.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvideorate.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvideoscale.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvideotestsrc.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvolume.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstautodetect.a recipe-sysroot/usr/lib/gstreamer-1.0/libgstvideofilter.a recipe-sysroot/usr/lib/libBrokenLocale.a recipe-sysroot/usr/lib/libBrokenLocale_pic.a recipe-sysroot/usr/lib/libanl.a recipe-sysroot/usr/lib/libanl_pic.a recipe-sysroot/usr/lib/libatomic.a recipe-sysroot/usr/lib/libatomic_ops.a recipe-sysroot/usr/lib/libatomic_ops_gpl.a ... more boost static libs ... recipe-sysroot/usr/lib/libc.a recipe-sysroot/usr/lib/libc_nonshared.a recipe-sysroot/usr/lib/libc_pic.a recipe-sysroot/usr/lib/libcidn_pic.a recipe-sysroot/usr/lib/libcrypt.a recipe-sysroot/usr/lib/libcrypt_pic.a recipe-sysroot/usr/lib/libcrypto.a recipe-sysroot/usr/lib/libdl.a recipe-sysroot/usr/lib/libdl_pic.a recipe-sysroot/usr/lib/libg.a recipe-sysroot/usr/lib/libgomp.a recipe-sysroot/usr/lib/libgstallocators-1.0.a recipe-sysroot/usr/lib/libgstaudio-1.0.a recipe-sysroot/usr/lib/libgstbase-1.0.a recipe-sysroot/usr/lib/libgstcheck-1.0.a recipe-sysroot/usr/lib/libgstcontroller-1.0.a recipe-sysroot/usr/lib/libgstfft-1.0.a recipe-sysroot/usr/lib/libgstpbutils-1.0.a recipe-sysroot/usr/lib/libgstreamer-1.0.a recipe-sysroot/usr/lib/libgstriff-1.0.a recipe-sysroot/usr/lib/libgstrtp-1.0.a recipe-sysroot/usr/lib/libgstrtsp-1.0.a recipe-sysroot/usr/lib/libgstrtspserver-1.0.a recipe-sysroot/usr/lib/libgstapp-1.0.a recipe-sysroot/usr/lib/libgstnet-1.0.a recipe-sysroot/usr/lib/libgstsdp-1.0.a recipe-sysroot/usr/lib/libgsttag-1.0.a recipe-sysroot/usr/lib/libgstvideo-1.0.a recipe-sysroot/usr/lib/libhistory.a recipe-sysroot/usr/lib/libitm.a recipe-sysroot/usr/lib/liblicensing.a recipe-sysroot/usr/lib/libm.a recipe-sysroot/usr/lib/libm_pic.a recipe-sysroot/usr/lib/libmcheck.a recipe-sysroot/usr/lib/libncurses++.a recipe-sysroot/usr/lib/libncurses++w.a recipe-sysroot/usr/lib/libnsl.a recipe-sysroot/usr/lib/libnsl_pic.a recipe-sysroot/usr/lib/libnss_compat_pic.a recipe-sysroot/usr/lib/libnss_db_pic.a recipe-sysroot/usr/lib/libnss_dns_pic.a recipe-sysroot/usr/lib/libnss_files_pic.a recipe-sysroot/usr/lib/libnss_hesiod_pic.a recipe-sysroot/usr/lib/libnss_nis_pic.a recipe-sysroot/usr/lib/libnss_nisplus_pic.a recipe-sysroot/usr/lib/libprotobuf-lite.a recipe-sysroot/usr/lib/libprotobuf.a recipe-sysroot/usr/lib/libprotoc.a recipe-sysroot/usr/lib/libpthread.a recipe-sysroot/usr/lib/libpthread_nonshared.a recipe-sysroot/usr/lib/libreadline.a recipe-sysroot/usr/lib/libresolv.a recipe-sysroot/usr/lib/libresolv_pic.a recipe-sysroot/usr/lib/librpcsvc.a recipe-sysroot/usr/lib/librt.a recipe-sysroot/usr/lib/librt_pic.a recipe-sysroot/usr/lib/libsqlite3.a recipe-sysroot/usr/lib/libssl.a recipe-sysroot/usr/lib/libssp.a recipe-sysroot/usr/lib/libssp_nonshared.a recipe-sysroot/usr/lib/libstdc++.a recipe-sysroot/usr/lib/libstdc++fs.a recipe-sysroot/usr/lib/libsupc++.a recipe-sysroot/usr/lib/libthread_db_pic.a recipe-sysroot/usr/lib/libutil.a recipe-sysroot/usr/lib/libutil_pic.a recipe-sysroot/usr/lib/libz.a recipe-sysroot/usr/lib/librt.a recipe-sysroot/usr/lib/libpthread.a recipe-sysroot/usr/lib/libm.a recipe-sysroot/usr/lib/libc.a
Does anybody know what is wrong? If more info is needed please ask. Thanks in advance!
Does anybody know what is wrong?
I suspect that you are not linking against GLIBC-2.27 from Yocto, but against some other GLIBC, though it is hard to see how that could happen.
Your first step should be to find out which libc.so.6 is actually being used. You can do so by adding -Wl,-t flag to your link line. Also add -Wl,-y,_IO_do_write while you are at it.
After you know which libc.so.6 is being used, run readelf -Ws /path/to/libc.so.6 | grep _IO_do_write to see what (if any) versioned symbols are defined in it.
I don't know if this matters or if it is normal (the function did not change since 2.17)?
Yes: that is normal -- the function didn't change its ABI since GLIBC-2.17, so that's the version that is attached to it.
I figured out what went wrong. The shared library is build using a CMAKE project and our own written FindGSTREAMER.cmake. To find gstreamer, among other things, a glob is used to find all the static libs. Because on my desktop I have gstreamer installed in its seperate location this works. With Yocto however this causes every static lib in the recipe-sysroot/usr/lib directory to be linked. Including every libc library (.a, _pic.a and .so). Apparently this causes the linker unable to resolve the symbols.
Correctly filtering the libraries needed by gstreamer fixed the problem.
When I try to build the following program:
#include <stdio.h>
int main(void)
{
printf("hello world\n");
return 0;
}
On OS X 10.6.4, with the following flags:
gcc -static -o blah blah.c
It returns this:
ld: library not found for -lcrt0.o
collect2: ld returned 1 exit status
Has anyone else encountered this, or is it something that noone else has been affected with yet? Any fixes?
Thanks
This won’t work. From the man page for gcc:
This option will not work on Mac OS X unless all libraries (including libgcc.a) have also been compiled with -static. Since neither a static version of libSystem.dylib nor crt0.o are provided, this option is not useful to most people.
Per Nate's answer, a completely static application is apparently not possible - see also man ld:
-static Produces a mach-o file that does not use the dyld. Only used building the kernel.
The problem in linking with static libraries is that, if both a static and a dynamic version of a library are found in the same directory, the dynamic version will be taken in preference. Three ways of avoiding this are:
Do not attempt to find them via the -L and -l options; instead, specify the full paths, to the libraries you want to use, on the compiler or linker command line.
$ g++ -Wall -Werror -o hi /usr/local/lib/libboost_unit_test_framework.a hi.cpp
Create a separate directory, containing symbolic links to the static libraries, use the -L option to have this directory searched first, and use the -l option to specify the libraries you want to use.
$ g++ -Wall -Werror -L ./staticBoostLib -l boost_unit_test_framework -o hi hi.cpp
Instead of creating a link of the same name in a different directory, create a link of a different name in the same directory, and specify that name in a -l argument.
$ g++ -Wall -Werror -l boost_unit_test_framework_static -o hi hi.cpp
You may also try LLVM LLD linker - I did prebuilt version for my two major OSes - https://github.com/VerKnowSys/Sofin-llds
This one allows me to link for exmple: "Qemu" properly - which is impossible with ld preinstalled by Apple.
And last one is - to build GCC yourself with libstdc++ (don't).
My build environment is CentOS 5. I have a third party library called libcunit. I installed it with autotools and it generates both libcunit.a and libcunit.so. I have my own application that links with a bunch of shared libraries. libcunit.a is in the current directory and libcunit.so and other shared libraries are in /usr/local/lib/. When I compile like:
gcc -o test test.c -L. libcunit.a -L/usr/local/lib -labc -lyz
I get a linkage error:
libcunit.a(Util.o): In function `CU_trim_left':
Util.c:(.text+0x346): undefined reference to `__ctype_b'
libcunit.a(Util.o): In function `CU_trim_right':
Util.c:(.text+0x3fd): undefined reference to `__ctype_b'
But when I compile with .so like:
gcc -o test test.c -L/usr/local/lib -lcunit -labc -lyz
it compiles fine and runs fine too.
Why is it giving error when linked statically with libcunit.a?
Why is it giving error when linked statically with libcunit.a
The problem is that your libcunit.a was built on an ancient Linux system, and depends on symbols which have been removed from libc (these symbols were used in glibc-2.2, and were removed from glibc-2.3 over 10 years ago). More exactly, these symbols have been hidden. They are made available for dynamic linking to old binaries (such as libcunit.so) but no new code can statically link to them (you can't create a new executable or shared library that references them).
You can observe this like so:
readelf -Ws /lib/x86_64-linux-gnu/libc.so.6 | egrep '\W__ctype_b\W'
769: 00000000003b9130 8 OBJECT GLOBAL DEFAULT 31 __ctype_b#GLIBC_2.2.5
readelf -Ws /usr/lib/x86_64-linux-gnu/libc.a | egrep '\W__ctype_b\W'
# no output
Didn't notice that the libcunit.a is actually found in your case and the problem with linakge is rather in the CUnit library itself. Employed Russian is absolutely right, and he's not talking about precompiled binary here. We understand that you've built it yourself. However, CUinit itself seems to be relying on the symbol from glibc which is not available for static linking anymore. As a result you have only 2 options:
File a report to the developers of CUnit about this and ask them to fix it;
Use dynamic linking.
Nevertheless, my recommendation about your style of static linkage still applies. -L. is in general bad practice. CUnit is a 3rd party library and should not be placed into the directory containing source files of your project. It should be rather installed in the same way as the dynamic version, i.e. like you have libcunit.so in /usr/local/lib. If you'd supply prefix to Autotools on the configure stage of CUnit, then Autotools would install everything properly. So if you want to link statically with CUnit, consider doing it in the following form:
gcc -o test test.c -L/usr/local/lib -Wl,-Bstatic -lcunit -Wl,-Bdynamic -labc -lyz
Is there any way we can get gcc to detect a duplicate symbol in static libraries vs the main code (Or another static library ?)
Here's the situation:
main.c erroneously contained a function definition, e.g. with the signature uint foohash(const char*)
foo.c also contains a function definition with the signature uint foohash(const char*)
foo.c and other source files are compiled to a static util library, which the main program links in, i.e. something like:
gcc -o main main.o util.o -L ./libs -lfooutils
So, now main.o and libs/libfooutils.a both contain a foohash function. Presumably the linker found that symbol in main.o and doesn't bother looking for it elsewhere.
Is there any way we can get gcc to detect such a situation ?
Indeed as Simon Richter stated, --whole-archive option can be useful. Try to change your command-line to:
gcc -o main main.o util.o -L ./libs -Wl,--whole-archive -lfooutils -Wl,--no-whole-archive
and you'll see a multiple definition error.
gcc calls the ld program for linking. The relevant ld options are:
--no-define-common
--traditional-format
--warn-common
See the man page for ld. These should be what you need to experiment with to get the warnings sought.
Short answer: no.
GCC does not actually do anything with libraries. It is the task of ld, the linker (called automatically by GCC) to pull in symbols from libraries, and that's really a fairly dumb tool.
The linker has lots of complex jiggery pokery for combining different types of data from different sources, and supporting different file formats, and all the evil little details of binary executables, but in the end, all it really does is look for undefined symbols and find the definitions.
What you can do is a link trace (pass -t to gcc) to see what comes from where. Or else run nm on all the object files and libraries in your system, and write a script to detect duplicates.
I have a C project that produces ten executables, all of which I would like to be linked in statically. The problem I am facing is that one of these executables uses a 3rd-party library of which only the shared-object version is available.
If I pass the -static flag to gcc, ld will error saying it can't find the library in question (I presume it's looking for the .a version) and the executable will not be built. Ideally, I would like to be able to tell 'ld' to statically link as much as it can and fail over to the shared object library if a static library cannot be found.
In the interium I tried something like gcc -static -lib1 -lib2 -shared -lib3rdparty foo.c -o foo.exe in hopes that 'ld' would statically link in lib1 and lib2 but only have a run-time dependence on lib3rdparty. Unfortunatly, this did not work as I intended; instead the -shared flag overwrote the -static flag and everything was compiled as shared-objects.
Is statically linking an all-or-nothing deal, or is there some way I can mix and match?
Looking at this thread you can see that it can be done. The guys at GNU suggest
gcc foo.c -Wl,-Bstatic -lbar -lbaz -lqux -Wl,-Bdynamic -lcorge -o foo.exe