Given a binary .a which links against libstdc++, is there any way of telling what v. of libstdc++ is needed?
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Is it possible to create a shared library which is itself statically linked, i.e. it does not depend on other shared libraries?
Let me be a little bit more concrete..
I want to create a shared library, say mylib.so, which makes use of some other special libraries (in my case its intel mkl and openMP). Since I have installed these libraries I can build mylib.so and include it in other programs without any problem.
However, if I want to use the library (or the executables including it) on another machine I first have to install all the intel stuff. Is there a way to avoid this? My first try was to add the option -static when building mylib.so but this doesn't seem to do anything..
I'm using icc..
Is it possible to create a shared library which is itself statically linked, i.e. it does not depend on other shared libraries?
Not on Linux, not when using GLIBC (your shared library will always depend on at least ld-linux*.so*).
I want to create a shared library, say mylib.so, which makes use of some other special libraries (in my case its intel mkl and openMP).
There is no problem1 statically linking Intel MKL and OpenMP libraries into mylib.so -- you just don't want to depend on these libraries dynamically (in other words, you are asking for an impossible thing which you don't actually need).
To do so, you need two things:
Link mylib.so with archive versions of the libraries you don't want to depend on dynamically, e.g. gcc -o mylib.so -shared mylib.c .../libmkl.a ...
The libraries which you want to statically link into mylib.so must have been built with position-independent code (i.e. with -fPIC flag).
Update:
What if the archived version isn't available?
Then you can't link it into your library.
Eg I'm using intel/oneapi/intelpython/latest/lib/libstdc++.so and there is no corresponding .a file..
This is a special case: you wouldn't want to link that version into your library even if it were available.
Instead, your program should use the version installed on the target system.
Having two separate versions of libstdc++ (e.g. one statically linked, and the other dynamically linked) into a single process will end very badly -- either with a crash, or with silent stack or heap corruption.
1 Note that linking in somebody else's library and distributing it may have licensing implications.
How I can to know what is a minimal version of glibc for gcc or binutils?
Regards.
binutils doesn't generally have a minimal glibc requirement because it doesn't have too much glibc-specific details in it. it's merely a collection of low level tools like an assembler and linker and objdumper all of which are built on code included in binutils.
gcc is a different beast -- it needs to know intimate details about C library capabilities. in the specific version of gcc you have, consult the INSTALL/index.html file (and particularly, the Prerequisites page) for the requirements.
I have downloaded a library that was compiled with a gcc 4.8 before the ABI change in GCC.
On my laptop (latest kubuntu) I have GCC 5.2. And When I installed boost, it seems that it used the new ABI but then I get the following link errors
undefined symbol.....__cxx11....
How can I install boost using old ABI with GCC5 ?
To my knowledge, there are no prebuilt Boost packages for the old ABI in the official Kubuntu repositories, so you will have to build Boost yourself. The building process is documented here.
Make sure you're building the same Boost version that was used when your library was built. If there were any Boost configuration macros defined, you will also have to define them the similar way. Otherwise you may encounter ABI incompatibilities between the library and Boost you've built.
In order to switch libstdc++ to the old ABI you will also have to define _GLIBCXX_USE_CXX11_ABI to 0, as described here. For example:
b2 -j8 variant=release define=_GLIBCXX_USE_CXX11_ABI=0 stage
You will also need to define the macro when you build your own code that uses Boost and the library.
The define property, along with many others, is documented here.
Given a GLIBCXX version of the stdc++ library (example GLIBCXX_3.4.17) given this version, where would one find documentation which specifies what features have been implemented?
Further is there a way to which given the SO NAME version will provide the this same document.
I am working on an embedded system which has an existing version of libstdc++; unfortunately the supplied cross compiler (g++) is at a greater version than what the stdc++ library on the target supports. Upgrading the stdc++ library on the target is not an option. Before I write a lot of code, to only find that it does not run on the target; I would like to know beforehand what is and is not supported.
I have found the GNU Documentation to be useful; however, I am hoping there is a document in which one can get what has been implemented given the symbol version and/or the SO NAME and I just have somehow missed it.
Thanks for any help in advance
given this version, where would one find documentation which specifies what features have been implemented?
You can map a GLIBCXX_A.B.C symbol version to a GCC release by checking
https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html
N.B. that won't be precise, because e.g. GCC 5.1 and GCC 5.2 both use GLIBCXX_3.4.21 in the shared library. To tell them apart check the __GLIBCXX__ macro defined by the libstdc++ headers, also documented on that page.
The manuals for libstdc++ releases are at
gcc.gnu.org/onlinedocs/gcc-[X.Y.Z]/libstdc++/manual/
e.g.
https://gcc.gnu.org/onlinedocs/gcc-5.3.0/libstdc++/manual/
Within that manual is a status table showing the implementation status for each standard, the table for C++11 support in GCC 5.3.0 is at
https://gcc.gnu.org/onlinedocs/gcc-5.3.0/libstdc++/manual/manual/status.html#status.iso.2011
Before I write a lot of code, to only find that it does not run on the target; I would like to know beforehand what is and is not supported.
It's not enough to simply avoid using features that aren't supported by the library on the target system. If you link with the cross-compiler then it will depend on the libstdc++.so from that cross-compiler, and will fail to run on the target system if it only has an older libstdc++.so
Upgrading the stdc++ library on the target is not an option.
Then you either need to link statically (creating large executables) or downgrade your cross-compiler to match the target. Or at least force it to use the headers and dynamic library from the same version as found on the target (by overriding the header and library search paths to point to copies of the older files), although that might not work, as the newer g++ might not be able to compile the older headers if they contain some invalid C++ that the older g++ didn't diagnose.
when I use boost library, I found for each library, usually it contains two versions.
for example, regex.a and regex-mt.a, which library I should link against? why?
mt is the thread-safe version. If your code uses threads, link the -mt version. Otherwise, link the regular one.